See tutors' answers!

Algebra ->  Tutoring on algebra.com -> See tutors' answers!      Log On


   
By Tutor
 | By Problem Number | 

Tutor:
New! Get regular updates about newly solved problems via algebra.com's RSS system.

Recent problems solved by 'MathLover1'

MathLover1 answered: 6623 problems
Jump to solutions: 0..29 , 30..59 , 60..89 , 90..119 , 120..149 , 150..179 , 180..209 , 210..239 , 240..269 , 270..299 , 300..329 , 330..359 , 360..389 , 390..419 , 420..449 , 450..479 , 480..509 , 510..539 , 540..569 , 570..599 , 600..629 , 630..659 , 660..689 , 690..719 , 720..749 , 750..779 , 780..809 , 810..839 , 840..869 , 870..899 , 900..929 , 930..959 , 960..989 , 990..1019 , 1020..1049 , 1050..1079 , 1080..1109 , 1110..1139 , 1140..1169 , 1170..1199 , 1200..1229 , 1230..1259 , 1260..1289 , 1290..1319 , 1320..1349 , 1350..1379 , 1380..1409 , 1410..1439 , 1440..1469 , 1470..1499 , 1500..1529 , 1530..1559 , 1560..1589 , 1590..1619 , 1620..1649 , 1650..1679 , 1680..1709 , 1710..1739 , 1740..1769 , 1770..1799 , 1800..1829 , 1830..1859 , 1860..1889 , 1890..1919 , 1920..1949 , 1950..1979 , 1980..2009 , 2010..2039 , 2040..2069 , 2070..2099 , 2100..2129 , 2130..2159 , 2160..2189 , 2190..2219 , 2220..2249 , 2250..2279 , 2280..2309 , 2310..2339 , 2340..2369 , 2370..2399 , 2400..2429 , 2430..2459 , 2460..2489 , 2490..2519 , 2520..2549 , 2550..2579 , 2580..2609 , 2610..2639 , 2640..2669 , 2670..2699 , 2700..2729 , 2730..2759 , 2760..2789 , 2790..2819 , 2820..2849 , 2850..2879 , 2880..2909 , 2910..2939 , 2940..2969 , 2970..2999 , 3000..3029 , 3030..3059 , 3060..3089 , 3090..3119 , 3120..3149 , 3150..3179 , 3180..3209 , 3210..3239 , 3240..3269 , 3270..3299 , 3300..3329 , 3330..3359 , 3360..3389 , 3390..3419 , 3420..3449 , 3450..3479 , 3480..3509 , 3510..3539 , 3540..3569 , 3570..3599 , 3600..3629 , 3630..3659 , 3660..3689 , 3690..3719 , 3720..3749 , 3750..3779 , 3780..3809 , 3810..3839 , 3840..3869 , 3870..3899 , 3900..3929 , 3930..3959 , 3960..3989 , 3990..4019 , 4020..4049 , 4050..4079 , 4080..4109 , 4110..4139 , 4140..4169 , 4170..4199 , 4200..4229 , 4230..4259 , 4260..4289 , 4290..4319 , 4320..4349 , 4350..4379 , 4380..4409 , 4410..4439 , 4440..4469 , 4470..4499 , 4500..4529 , 4530..4559 , 4560..4589 , 4590..4619 , 4620..4649 , 4650..4679 , 4680..4709 , 4710..4739 , 4740..4769 , 4770..4799 , 4800..4829 , 4830..4859 , 4860..4889 , 4890..4919 , 4920..4949 , 4950..4979 , 4980..5009 , 5010..5039 , 5040..5069 , 5070..5099 , 5100..5129 , 5130..5159 , 5160..5189 , 5190..5219 , 5220..5249 , 5250..5279 , 5280..5309 , 5310..5339 , 5340..5369 , 5370..5399 , 5400..5429 , 5430..5459 , 5460..5489 , 5490..5519 , 5520..5549 , 5550..5579 , 5580..5609 , 5610..5639 , 5640..5669 , 5670..5699 , 5700..5729 , 5730..5759 , 5760..5789 , 5790..5819 , 5820..5849 , 5850..5879 , 5880..5909 , 5910..5939 , 5940..5969 , 5970..5999 , 6000..6029 , 6030..6059 , 6060..6089 , 6090..6119 , 6120..6149 , 6150..6179 , 6180..6209 , 6210..6239 , 6240..6269 , 6270..6299 , 6300..6329 , 6330..6359 , 6360..6389 , 6390..6419 , 6420..6449 , 6450..6479 , 6480..6509 , 6510..6539 , 6540..6569 , 6570..6599 , 6600..6629, >>Next

Graphs/656155: 3y - 12x = 18
1 solutions

Answer 409364 by MathLover1(6625) About Me  on 2012-09-24 10:55:37 (Show Source):
You can put this solution on YOUR website!
3y+-+12x+=+18...first simplify, both sides divide by 3

3y%2F3+-+12x%2F3+=+18%2F3



y+-+4x+=+6

y+=4x+%2B6..to find zeros, set y=0 and solve for x
0+=4x+%2B6
4x+=+-6+
x+=+-6%2F4+
x+=+-3%2F2+
and
set x=0 and solve for y
y+=4%2A0+%2B6
y+=+6+


+graph%28+600%2C+600%2C+-10%2C10%2C+-10%2C+10%2C+4x+%2B6%29+





Quadratic_Equations/656156: Zero`s of 6x*6x-5x+7 & 6x*6x+5x-7
1 solutions

Answer 409362 by MathLover1(6625) About Me  on 2012-09-24 10:31:02 (Show Source):
You can put this solution on YOUR website!
Zero`s of 6x%2A6x-5x%2B7=0
36x%5E2-5x%2B7=0 ..use quadratic formula
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+

x+=+%28-%28-5%29+%2B-+sqrt%28+%28-5%29%5E2-4%2A36%2A7+%29%29%2F%282%2A36%29+

x+=+%285+%2B-+sqrt%28+25-1008+%29%29%2F72+

x+=+%285+%2B-+sqrt%28+-983+%29%29%2F72+

x+=+%285+%2B-+sqrt%28+-1%2A983+%29%29%2F72+

x+=+%285+%2B-+5.6i%29%2F72+

x+=+5%2F72+%2B-+5.6i%2F72+

x+=0.007+%2B-+0.08i+
solutions:
x+=0.007+%2B+0.08i+
and
x+=0.007+-+0.08i+


+graph%28+600%2C+600%2C+-5%2C+5%2C+-5%2C+20%2C+36x%5E2-5x%2B7%29+

&

6x%2A6x%2B5x-7=0

36x%5E2%2B5x-7=0 ..use quadratic formula

x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+

x+=+%28-%285%29+%2B-+sqrt%28+%285%29%5E2-4%2A36%2A%28-7%29+%29%29%2F%282%2A36%29+

x+=+%28-5+%2B-+sqrt%28+25%2B1008+%29%29%2F72+

x+=+%28-5+%2B-+sqrt%28+1033+%29%29%2F72+

x+=+%28-5+%2B-+32.14%29%2F72+

x+=+-5%2F72+%2B-+32.14%2F72+

x+=-0.007+%2B-+0.45+
solutions:
x+=-0.007+%2B+0.45+
x+=0.443+
and
x+=-0.007+-+0.45+
x+=-0.457+


+graph%28+600%2C+600%2C+-5%2C+5%2C+-15%2C+15%2C+36x%5E2%2B5x-7%29+





Complex_Numbers/656149: x^2+8x+20=0
1 solutions

Answer 409359 by MathLover1(6625) About Me  on 2012-09-24 10:11:59 (Show Source):
You can put this solution on YOUR website!
x%5E2%2B8x%2B20=0...use quadratic formula to solve for x

x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ ...note that a=1, b=8 and c=20

x+=+%28-8+%2B-+sqrt%28+8%5E2-4%2A1%2A20+%29%29%2F%282%2A1%29+

x+=+%28-8+%2B-+sqrt%28+64-80+%29%29%2F2+

x+=+%28-8+%2B-+sqrt%28+-16+%29%29%2F2+

x+=+%28-8+%2B-+sqrt%28+-1%2A16+%29%29%2F2+

x+=+%28-8+%2B-+4i%29%2F2+

x+=+-8%2F2+%2B-+4i%2F2+

x+=+-4+%2B-+2i+

solutions:
x+=+-4+%2B+2i+
or
x+=+-4+-+2i+

+graph%28+600%2C+600%2C+-10%2C+10%2C+-5%2C+25%2C+x%5E2%2B8x%2B20%29+





Linear-equations/656140: solving by elimination
5x-7y=-49
3x+9y=-3
1 solutions

Answer 409358 by MathLover1(6625) About Me  on 2012-09-24 10:02:31 (Show Source):
You can put this solution on YOUR website!

Solved by pluggable solver: Solving a System of Linear Equations by Elimination/Addition


Lets start with the given system of linear equations

5%2Ax-7%2Ay=-49
3%2Ax%2B9%2Ay=-3

In order to solve for one variable, we must eliminate the other variable. So if we wanted to solve for y, we would have to eliminate x (or vice versa).

So lets eliminate x. In order to do that, we need to have both x coefficients that are equal but have opposite signs (for instance 2 and -2 are equal but have opposite signs). This way they will add to zero.

So to make the x coefficients equal but opposite, we need to multiply both x coefficients by some number to get them to an equal number. So if we wanted to get 5 and 3 to some equal number, we could try to get them to the LCM.

Since the LCM of 5 and 3 is 15, we need to multiply both sides of the top equation by 3 and multiply both sides of the bottom equation by -5 like this:

3%2A%285%2Ax-7%2Ay%29=%28-49%29%2A3 Multiply the top equation (both sides) by 3
-5%2A%283%2Ax%2B9%2Ay%29=%28-3%29%2A-5 Multiply the bottom equation (both sides) by -5


So after multiplying we get this:
15%2Ax-21%2Ay=-147
-15%2Ax-45%2Ay=15

Notice how 15 and -15 add to zero (ie 15%2B-15=0)


Now add the equations together. In order to add 2 equations, group like terms and combine them
%2815%2Ax-15%2Ax%29-21%2Ay-45%2Ay%29=-147%2B15

%2815-15%29%2Ax-21-45%29y=-147%2B15

cross%2815%2B-15%29%2Ax%2B%28-21-45%29%2Ay=-147%2B15 Notice the x coefficients add to zero and cancel out. This means we've eliminated x altogether.



So after adding and canceling out the x terms we're left with:

-66%2Ay=-132

y=-132%2F-66 Divide both sides by -66 to solve for y



y=2 Reduce


Now plug this answer into the top equation 5%2Ax-7%2Ay=-49 to solve for x

5%2Ax-7%282%29=-49 Plug in y=2


5%2Ax-14=-49 Multiply



5%2Ax=-49%2B14 Subtract -14 from both sides

5%2Ax=-35 Combine the terms on the right side

cross%28%281%2F5%29%285%29%29%2Ax=%28-35%29%281%2F5%29 Multiply both sides by 1%2F5. This will cancel out 5 on the left side.


x=-7 Multiply the terms on the right side


So our answer is

x=-7, y=2

which also looks like

(-7, 2)

Notice if we graph the equations (if you need help with graphing, check out this solver)

5%2Ax-7%2Ay=-49
3%2Ax%2B9%2Ay=-3

we get



graph of 5%2Ax-7%2Ay=-49 (red) 3%2Ax%2B9%2Ay=-3 (green) (hint: you may have to solve for y to graph these) and the intersection of the lines (blue circle).


and we can see that the two equations intersect at (-7,2). This verifies our answer.


Geometry_proofs/656010: AB+BC=AC
AB=XY
XY+BC=AC
What is the reason?
1 solutions

Answer 409336 by MathLover1(6625) About Me  on 2012-09-23 22:06:03 (Show Source):
You can put this solution on YOUR website!
reason: use of transitive property of segment length



Graphs/655963: what is the equation of a line passing through (-2, -1) and (6, 3)?
1 solutions

Answer 409315 by MathLover1(6625) About Me  on 2012-09-23 20:28:46 (Show Source):
You can put this solution on YOUR website!

Solved by pluggable solver: FIND EQUATION of straight line given 2 points
hahaWe are trying to find equation of form y=ax+b, where a is slope, and b is intercept, which passes through points (x1, y1) = (-2, -1) and (x2, y2) = (6, 3).
Slope a is a+=+%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29+=+%283--1%29%2F%286--2%29+=+0.5.
Intercept is found from equation a%2Ax%5B1%5D%2Bb+=+y%5B1%5D, or 0.5%2A-2+%2Bb+=+0. From that,
intercept b is b=y%5B1%5D-a%2Ax%5B1%5D, or b=-1-0.5%2A-2+=+0.

y=(0.5)x + (0)

Your graph:




expressions/655947: By which property is the equation 1 • 0 • (-1) = 0 true?
A. Identify Property of Multiplication
B. Multiplication Property of Zero
C. Multiplication Property of -1
D. Inverse Property of Addition
1 solutions

Answer 409311 by MathLover1(6625) About Me  on 2012-09-23 20:21:13 (Show Source):
You can put this solution on YOUR website!
1+%2A+0+%2A+%28-1%29+=+0+....since one multiplier is 0, your
answer is: B. Multiplication Property of Zero



Length-and-distance/655727: M is the midpoint of RT. RM = x and RT = 4x - 6. Find the value of x.
1 solutions

Answer 409258 by MathLover1(6625) About Me  on 2012-09-23 14:58:20 (Show Source):
You can put this solution on YOUR website!

if M is the midpoint of RT, then RM=MT
given:
RM+=+x and RT+=+4x+-+6
Find: the value of+x
----------------------------------------
if RM+=+x, then MT+=+x
RT=RM%2BMT
4x+-+6=x%2Bx..solve for x
4x+-+6=2x
4x+-2x=6
2x=6
highlight%28x=3%29



Sequences-and-series/655658: Write a linear function where f(2)=4,f(4)=2 and f(3)=3.
1 solutions

Answer 409227 by MathLover1(6625) About Me  on 2012-09-23 12:59:30 (Show Source):
You can put this solution on YOUR website!
If f%282%29=4,f%284%29=2, f%283%29=3, then the graph of the function contains the point (2,4),(4,2), and (3,3).
Use the two point form of an equation of a straight line and the points (2,4),(4,2):
f%28x%29-y1=%28%28y1-y2%29%2F%28x1-x2%29%29%28x-x1%29 where (x1,y1)and (x2,y2) are the coordinates of the given points.
f%28x%29-4=%28%284-2%29%2F%282-4%29%29%28x-2%29

f%28x%29-4=%282%2F-2%29%28x-2%29

f%28x%29-4=-1%28x-2%29
f%28x%29-4=-x%2B2
f%28x%29=-x%2B2%2B4
highlight%28f%28x%29=-x%2B6%29

+graph%28+600%2C+600%2C+-10%2C+10%2C+-10%2C+10%2C+-x%2B6%29+

here is a proof that all three of given points lie on this line

Solved by pluggable solver: To determine if 3 points lie in a line
The 3 points lie on a same plane. For all points to lie on a line they should satisfy the equation of a line. Hence any two points taken on a line should calculate to the same slope of a line.

In order to prove the 3 points to lie on a line, as there exists a unique line containing three points and every line has a unique slope.
Hence it will be sufficient to prove that the slope calculated taking 2 points at a time should be equal.


Slope of line taking points (X1,Y1) and (X2,Y2) is

slope+=+%28Y2-Y1%29%2F%28X2-X1%29


slope+=+%28%282-4%29%2F%284-2%29%29+=+-1 ........................(1)



Slope of line taking points (X3,Y3) and (X1,Y1) is

slope+=+%28Y3-Y1%29%2F%28X3-X1%29


slope+=+%28%283-4%29%2F%283-2%29%29+=+-1 ........................(2)



From conditions (1) and (2)


The slopes are equal hence the 3 points can lie on same line.


If the slope calculated from points (X2,Y2) and (X3,Y3) comes out to be same then it is confirmed that the 3 points lie on a same line.



slope+=+%28Y3-Y2%29%2F%28X3-X2%29


slope+=+%28%283-2%29%2F%283-4%29%29+=+-1 ........................(3)


From (1),(2) and (3)

Hence, It is proved that the 3 points lie on same line.


To read more on equations of a line refer to articles on wikipedia





test/655406: Through :(-4,-4), parallel to x=0
1 solutions

Answer 409112 by MathLover1(6625) About Me  on 2012-09-22 18:23:48 (Show Source):
You can put this solution on YOUR website!
Slope Intercept form:
y=mx%2Bb
y=-4
m=?
x=-4
b=?
Find+m:
Since you know your line is parallel to x=0 then we know it is a vertical line on the y-axis that has points of [(0,1), (0,2), etc...]
take points: (0,1) and given point (-4,-4)
m+=+%28y2+-+y1%29+%2F+%28x2+-+x1%29...
m+=+%28-1+-+%28-4%29%29+%2F+%28-4+-+0%29
m+=+%28-1+%2B4%29+%2F+%28-4+%29
m+=+3+%2F+%28-4+%29
m+=+-%283%2F4%29



So.... back to y=mx%2Bb
-4+=+-%283%2F4%29%28-4%29+%2B+b
-4=+3+%2B+b
-4-3=+b
b+=-7

Finally y+=++-%283%2F4%29x+-7 or y+=++-%280.75%29x+-7
+graph%28+600%2C+600%2C+-10%2C+10%2C+-10%2C+10%2C+-%283%2F4%29x+-7%29+


or, you can find it this way: first slope, then equation of line through the given point and slope


Solved by pluggable solver: FIND a line by slope and one point

What we know about the line whose equation we are trying to find out:

  • it goes through point (-4, -4)

  • it has a slope of -0.75



First, let's draw a diagram of the coordinate system with point (-4, -4) plotted with a little blue dot:



Write this down: the formula for the equation, given point x%5B1%5D%2C+y%5B1%5D and intercept a, is

y=ax+%2B+%28y%5B1%5D-a%2Ax%5B1%5D%29 (see a paragraph below explaining why this formula is correct)

Given that a=-0.75, and system%28+x%5B1%5D+=+-4%2C+y%5B1%5D+=+-4+%29+, we have the equation of the line:

y=-0.75%2Ax+%2B+-7

Explanation: Why did we use formula y=ax+%2B+%28y%5B1%5D+-+a%2Ax%5B1%5D%29 ? Explanation goes here. We are trying to find equation y=ax+b. The value of slope (a) is already given to us. We need to find b. If a point (x%5B1%5D, y%5B1%5D) lies on the line, it means that it satisfies the equation of the line. So, our equation holds for (x%5B1%5D, y%5B1%5D): y%5B1%5D+=+a%2Ax%5B1%5D%2Bb Here, we know a, x%5B1%5D, and y%5B1%5D, and do not know b. It is easy to find out: b=y%5B1%5D-a%2Ax%5B1%5D. So, then, the equation of the line is: +y=ax%2B%28y%5B1%5D-a%2Ax%5B1%5D%29+.

Here's the graph:








Expressions-with-variables/655417: what is the distance between(7,3) and (-1,-4)?
1 solutions

Answer 409101 by MathLover1(6625) About Me  on 2012-09-22 17:58:57 (Show Source):
You can put this solution on YOUR website!

Solved by pluggable solver: Distance Formula to determine length on coordinate plane
The distance (d) between two points is given by the following formula:

d=sqrt%28%28x2-x1%29%5E2+%2B+%28y2-y1%29%5E2%29

Thus in our case, the required distance is
d=sqrt%28%28-1-7%29%5E2+%2B+%28-4-3%29%5E2%29=+10.6301458127346+


For more on this concept, refer to Distance formula.


Equations/655421: Find f(3) when f(x)=x^2-4x+7
1 solutions

Answer 409099 by MathLover1(6625) About Me  on 2012-09-22 17:57:31 (Show Source):


Linear-equations/655358: x+y=
1 solutions

Answer 409094 by MathLover1(6625) About Me  on 2012-09-22 17:31:49 (Show Source):
You can put this solution on YOUR website!
your question is incomplete!!! post it again


expressions/655412: 2(x − 3) 2x − 6
Prove, in complete sentences, whether the left expression is equal to the right expression and discuss which property applies.
1 solutions

Answer 409092 by MathLover1(6625) About Me  on 2012-09-22 17:30:36 (Show Source):
You can put this solution on YOUR website!
2%28x+-+3%29...left expression
+2x+-6... right expression
if the left expression is equal to the right expression, then will be
2%28x+-+3%29=2x+-+6...first multiply 2%28x-+3%29
2%2Ax+-3%2A2=2x-+6
2x+-+6=2x+-+6...both sides of the equation are same, means it is true
consequently, we can say that left expression is+equal to right expression


Quadratic_Equations/655375: Suppose x1 and x2 are two solutions of the equation x^2+bx+c=0.Find x_1+x_2 and x_1 x_2.
Hint: What are the solutions?

1 solutions

Answer 409087 by MathLover1(6625) About Me  on 2012-09-22 16:55:14 (Show Source):
You can put this solution on YOUR website!
x1 and x2 are two solutions of the equation x%5E2%2Bbx%2Bc=0

x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+...since a=1, we have

x+=+%28-b+%2B-+sqrt%28+b%5E2-4c+%29%29%2F2+

so, the solutions are:

x_1+=+%28-b+%2Bsqrt%28+b%5E2-4c+%29%29%2F2+

x_2+=+%28-b+-+sqrt%28+b%5E2-4c+%29%29%2F2+



now find x_1%2Bx_2 and x_1+%2A_2

x_1%2Bx_2=%28-b+%2Bsqrt%28+b%5E2-4c+%29%29%2F2%2B%28-b+-+sqrt%28+b%5E2-4c+%29%29%2F2

x_1%2Bx_2=%28-b+%2Bsqrt%28+b%5E2-4c+%29-b%2Bsqrt%28+b%5E2-4c+%29%29%2F2

x_1%2Bx_2=%28-2b+%2B2sqrt%28+b%5E2-4c+%29%29%2F2

x_1%2Bx_2=2%28-b+%2Bsqrt%28+b%5E2-4c+%29%29%2F2

x_1%2Bx_2=cross%282%29%28-b+%2Bsqrt%28+b%5E2-4c+%29%29%2Fcross%282%29

x_1%2Bx_2=-b+%2Bsqrt%28+b%5E2-4c+%29


and



x_1+%2A_2=%28-b+%2Bsqrt%28+b%5E2-4c+%29%29%2A%28-b+-+sqrt%28+b%5E2-4c+%29%29%2F%282%2A2%29





x_1+%2A_2=%28b%5E2+%2B+b%5E2-4c+%29%2F4

x_1+%2A_2=%282b%5E2-4c+%29%2F4

x_1+%2A_2=2%28b%5E2-2c+%29%2F4

x_1+%2A_2=cross%282%29%28b%5E2-2c+%29%2Fcross%284%29

x_1+%2A_2=%28b%5E2-2c+%29%2F2









Polynomials-and-rational-expressions/655345: finding zeros of a polynomial function f(x)=5x^4+15x^2 +10

1 solutions

Answer 409082 by MathLover1(6625) About Me  on 2012-09-22 16:13:18 (Show Source):
You can put this solution on YOUR website!
f%28x%29=5x%5E4%2B15x%5E2+%2B10+
f%28x%29=5%28x%5E4%2B3x%5E2%2B2%29+
f%28x%29=5%28x%5E4%2B2x%5E2%2Bx%5E2%2B2%29+

f%28x%29=5%28%28x%5E4%2B2x%5E2%29%2B%28x%5E2%2B2%29%29+
f%28x%29=5%28x%5E2%28x%5E2%2B2%29%2B%28x%5E2%2B2%29%29+
f%28x%29=5%28x%5E2%2B1%29%28x%5E2%2B2%29%29+
set f%28x%29=0 to fins solutions:
if %28x%5E2%2B1%29+...->....x%5E2=-1+.->....x=-i+ or x=i+..complex roots
if %28x%5E2%2B2%29=0+...->....x%5E2=-2+...->....x%5E2=sqrt%28-2%29...->....x=-i%2Asqrt%282%29+ or x=i%2Asqrt%282%29+....complex roots
so, roots are: complex roots
x=-i+
x=i+
x=-i%2Asqrt%282%29+
x=i%2Asqrt%282%29+




Surface-area/655350: PLEASE HELP! The diameter of a circle is (x+2) units. Express the area of the square in the figure as a polynomial
it is a circle with a line going through the middle, and two arrows going opposite directions below that with x+2 in the center.
http://i49.tinypic.com/2w7pyjp.png < This is a picture for a visual
thanks.
1 solutions

Answer 409079 by MathLover1(6625) About Me  on 2012-09-22 15:33:14 (Show Source):
You can put this solution on YOUR website!
you are given: the diameter of a circle is %28x%2B2%29 units
you need to express the area of the square in the figure as a polynomial
as you know, the area of the square is A=a%5E2 where a is the side of the square
if you take a close look at your picture, you will see that a=%28x%2B2%29 units
so,the area of the square will be:
A=a%5E2units%5E2
A=%28x%2B2%29%5E2units%5E2
A=%28x%5E2%2B4x%2B4%29units%5E2
so, your answer is: %28x%5E2%2B4x%2B4%29units%5E2


Surface-area/655352: PLEASE HELP-
Whats the area of the shaded figure? Round your answer to the nearest tenth.
Can anyone show me step by step how to figure this out? 12.5cm is in the inside. 8.4 is at the bottom. THANKS!
http://i46.tinypic.com/2u8koes.png < picture of the problem with multiple choice answers
1 solutions

Answer 409078 by MathLover1(6625) About Me  on 2012-09-22 15:22:18 (Show Source):
You can put this solution on YOUR website!
if you look closely at shaded area, you will see that that area could be calculated as following:
you have a square inside ellipse with sides 12.5cm and 8.4cm, so its
area is:
Area_square+=12.5cm%2A8.4cm
Area_square+=105cm%5E2
than you have two half circles with same diameter of 8.4cm that you should deduct from the area of the square, and these two halves make one full circle with area C=r%5E2pi where r=8.4cm%2F2=4.2cm
so, we have
Area_circle1+=+r1%5E2pi
Area_circle1+=+%284.2cm%29%5E2%2A3.14
Area_circle1+=+55.3896%5E2cm%5E2
find their difference:
Area_square+-Area_circle1=105cm%5E2-55.3896%5E2cm%5E2
Area_square+-Area_circle1=49.6104cm%5E2
finaly, you have two half circles, one on left and one on right side of the square, that make one full circle...its diameter is 12.5cm; so, its radius is r2=6.25cm and the area will be
Area_circle2+=+r2%5E2pi
Area_circle2+=+%286.25cm%29%5E2pi
Area_circle2+=122.65625cm%5E2

now, your shaded area will be:%28Area_square+-Area_circle1%29+%2BArea_circle2
%28Area_square+-Area_circle1%29+%2BArea_circle2=49.6104cm%5E2%2B122.65625cm%5E2
%28Area_square+-Area_circle1%29+%2BArea_circle2=172.26665cm%5E2 ...round to one decimal place

%28Area_square+-Area_circle1%29+%2BArea_circle2=172.3cm%5E2

so, your answer is 172.3cm%5E2



Equations/655303: Help me solve this equation: x/8 + 12 = -5
1 solutions

Answer 409066 by MathLover1(6625) About Me  on 2012-09-22 13:31:06 (Show Source):


Linear-systems/655332: which ordered pair is a solution to hte system 3x+2y=-9 and 5x-3y=4
1 solutions

Answer 409062 by MathLover1(6625) About Me  on 2012-09-22 13:10:55 (Show Source):
You can put this solution on YOUR website!

Solved by pluggable solver: Solve the System of Equations by Graphing



Start with the given system of equations:


3x%2B2y=-9

5x-3y=4





In order to graph these equations, we need to solve for y for each equation.




So let's solve for y on the first equation


3x%2B2y=-9 Start with the given equation



2y=-9-3x Subtract 3+x from both sides



2y=-3x-9 Rearrange the equation



y=%28-3x-9%29%2F%282%29 Divide both sides by 2



y=%28-3%2F2%29x%2B%28-9%29%2F%282%29 Break up the fraction



y=%28-3%2F2%29x-9%2F2 Reduce



Now lets graph y=%28-3%2F2%29x-9%2F2 (note: if you need help with graphing, check out this solver)



+graph%28+600%2C+600%2C+-10%2C+10%2C+-10%2C+10%2C+%28-3%2F2%29x-9%2F2%29+ Graph of y=%28-3%2F2%29x-9%2F2




So let's solve for y on the second equation


5x-3y=4 Start with the given equation



-3y=4-5x Subtract 5+x from both sides



-3y=-5x%2B4 Rearrange the equation



y=%28-5x%2B4%29%2F%28-3%29 Divide both sides by -3



y=%28-5%2F-3%29x%2B%284%29%2F%28-3%29 Break up the fraction



y=%285%2F3%29x-4%2F3 Reduce





Now lets add the graph of y=%285%2F3%29x-4%2F3 to our first plot to get:


Graph of y=%28-3%2F2%29x-9%2F2(red) and y=%285%2F3%29x-4%2F3(green)


From the graph, we can see that the two lines intersect at the point (-1,-3) (note: you might have to adjust the window to see the intersection)


Square-cubic-other-roots/655284: the sum of the square of x and 5 in word problem
1 solutions

Answer 409028 by MathLover1(6625) About Me  on 2012-09-22 09:55:33 (Show Source):
You can put this solution on YOUR website!

if you have "the sum", put + sign between x and 5
if you have square of x, write it as sqrt%28x%29
then you have: sqrt%28x%29%2B5


Linear-systems/655283: I need help on understanding how to solve this problem using substitution and elimination. Please show me how:
4x+5y=13
4x+3y=9

1 solutions

Answer 409026 by MathLover1(6625) About Me  on 2012-09-22 09:51:21 (Show Source):
You can put this solution on YOUR website!

solving linear system by substitution:
Solved by pluggable solver: Solving a linear system of equations by subsitution


Lets start with the given system of linear equations

4%2Ax%2B5%2Ay=13
4%2Ax%2B3%2Ay=9

Now in order to solve this system by using substitution, we need to solve (or isolate) one variable. I'm going to choose y.

Solve for y for the first equation

5%2Ay=13-4%2AxSubtract 4%2Ax from both sides

y=%2813-4%2Ax%29%2F5 Divide both sides by 5.


Which breaks down and reduces to



y=13%2F5-%284%2F5%29%2Ax Now we've fully isolated y

Since y equals 13%2F5-%284%2F5%29%2Ax we can substitute the expression 13%2F5-%284%2F5%29%2Ax into y of the 2nd equation. This will eliminate y so we can solve for x.


4%2Ax%2B3%2Ahighlight%28%2813%2F5-%284%2F5%29%2Ax%29%29=9 Replace y with 13%2F5-%284%2F5%29%2Ax. Since this eliminates y, we can now solve for x.

4%2Ax%2B3%2A%2813%2F5%29%2B3%28-4%2F5%29x=9 Distribute 3 to 13%2F5-%284%2F5%29%2Ax

4%2Ax%2B39%2F5-%2812%2F5%29%2Ax=9 Multiply



4%2Ax%2B39%2F5-%2812%2F5%29%2Ax=9 Reduce any fractions

4%2Ax-%2812%2F5%29%2Ax=9-39%2F5 Subtract 39%2F5 from both sides


4%2Ax-%2812%2F5%29%2Ax=45%2F5-39%2F5 Make 9 into a fraction with a denominator of 5


4%2Ax-%2812%2F5%29%2Ax=6%2F5 Combine the terms on the right side



%2820%2F5%29%2Ax-%2812%2F5%29x=6%2F5 Make 4 into a fraction with a denominator of 5

%288%2F5%29%2Ax=6%2F5 Now combine the terms on the left side.


cross%28%285%2F8%29%288%2F5%29%29x=%286%2F5%29%285%2F8%29 Multiply both sides by 5%2F8. This will cancel out 8%2F5 and isolate x

So when we multiply 6%2F5 and 5%2F8 (and simplify) we get



x=3%2F4 <---------------------------------One answer

Now that we know that x=3%2F4, lets substitute that in for x to solve for y

4%283%2F4%29%2B3%2Ay=9 Plug in x=3%2F4 into the 2nd equation

3%2B3%2Ay=9 Multiply

3%2Ay=9-3Subtract 3 from both sides

3%2Ay=6 Combine the terms on the right side

cross%28%281%2F3%29%283%29%29%2Ay=%286%2F1%29%281%2F3%29 Multiply both sides by 1%2F3. This will cancel out 3 on the left side.

y=6%2F3 Multiply the terms on the right side


y=2 Reduce


So this is the other answer


y=2<---------------------------------Other answer


So our solution is

x=3%2F4 and y=2

which can also look like

(3%2F4,2)

Notice if we graph the equations (if you need help with graphing, check out this solver)

4%2Ax%2B5%2Ay=13
4%2Ax%2B3%2Ay=9

we get


graph of 4%2Ax%2B5%2Ay=13 (red) and 4%2Ax%2B3%2Ay=9 (green) (hint: you may have to solve for y to graph these) intersecting at the blue circle.


and we can see that the two equations intersect at (3%2F4,2). This verifies our answer.


-----------------------------------------------------------------------------------------------
Check:

Plug in (3%2F4,2) into the system of equations


Let x=3%2F4 and y=2. Now plug those values into the equation 4%2Ax%2B5%2Ay=13

4%2A%283%2F4%29%2B5%2A%282%29=13 Plug in x=3%2F4 and y=2


12%2F4%2B10=13 Multiply


52%2F4=13 Add


13=13 Reduce. Since this equation is true the solution works.


So the solution (3%2F4,2) satisfies 4%2Ax%2B5%2Ay=13



Let x=3%2F4 and y=2. Now plug those values into the equation 4%2Ax%2B3%2Ay=9

4%2A%283%2F4%29%2B3%2A%282%29=9 Plug in x=3%2F4 and y=2


12%2F4%2B6=9 Multiply


36%2F4=9 Add


9=9 Reduce. Since this equation is true the solution works.


So the solution (3%2F4,2) satisfies 4%2Ax%2B3%2Ay=9


Since the solution (3%2F4,2) satisfies the system of equations


4%2Ax%2B5%2Ay=13
4%2Ax%2B3%2Ay=9


this verifies our answer.






solving linear system by elimination:

Solved by pluggable solver: Solving a System of Linear Equations by Elimination/Addition


Lets start with the given system of linear equations

4%2Ax%2B5%2Ay=13
4%2Ax%2B3%2Ay=9

In order to solve for one variable, we must eliminate the other variable. So if we wanted to solve for y, we would have to eliminate x (or vice versa).

So lets eliminate x. In order to do that, we need to have both x coefficients that are equal but have opposite signs (for instance 2 and -2 are equal but have opposite signs). This way they will add to zero.

So to make the x coefficients equal but opposite, we need to multiply both x coefficients by some number to get them to an equal number. So if we wanted to get 4 and 4 to some equal number, we could try to get them to the LCM.

Since the LCM of 4 and 4 is 4, we need to multiply both sides of the top equation by 1 and multiply both sides of the bottom equation by -1 like this:

1%2A%284%2Ax%2B5%2Ay%29=%2813%29%2A1 Multiply the top equation (both sides) by 1
-1%2A%284%2Ax%2B3%2Ay%29=%289%29%2A-1 Multiply the bottom equation (both sides) by -1


So after multiplying we get this:
4%2Ax%2B5%2Ay=13
-4%2Ax-3%2Ay=-9

Notice how 4 and -4 add to zero (ie 4%2B-4=0)


Now add the equations together. In order to add 2 equations, group like terms and combine them
%284%2Ax-4%2Ax%29%2B%285%2Ay-3%2Ay%29=13-9

%284-4%29%2Ax%2B%285-3%29y=13-9

cross%284%2B-4%29%2Ax%2B%285-3%29%2Ay=13-9 Notice the x coefficients add to zero and cancel out. This means we've eliminated x altogether.



So after adding and canceling out the x terms we're left with:

2%2Ay=4

y=4%2F2 Divide both sides by 2 to solve for y



y=2 Reduce


Now plug this answer into the top equation 4%2Ax%2B5%2Ay=13 to solve for x

4%2Ax%2B5%282%29=13 Plug in y=2


4%2Ax%2B10=13 Multiply



4%2Ax=13-10 Subtract 10 from both sides

4%2Ax=3 Combine the terms on the right side

cross%28%281%2F4%29%284%29%29%2Ax=%283%29%281%2F4%29 Multiply both sides by 1%2F4. This will cancel out 4 on the left side.


x=3%2F4 Multiply the terms on the right side


So our answer is

x=3%2F4, y=2

which also looks like

(3%2F4, 2)

Notice if we graph the equations (if you need help with graphing, check out this solver)

4%2Ax%2B5%2Ay=13
4%2Ax%2B3%2Ay=9

we get



graph of 4%2Ax%2B5%2Ay=13 (red) 4%2Ax%2B3%2Ay=9 (green) (hint: you may have to solve for y to graph these) and the intersection of the lines (blue circle).


and we can see that the two equations intersect at (3%2F4,2). This verifies our answer.


Equations/655267: Explain and answer the question
[3a * -7b + b] * [{(sqrt 3)/2}* a^2*b]
note
in the second bracket, you have to find the square root of 3 and then divide in by 2 after that multiply by a square . then multiply by b
1 solutions

Answer 409022 by MathLover1(6625) About Me  on 2012-09-22 09:46:43 (Show Source):
You can put this solution on YOUR website!
%283a+%2A+-7b+%2B+b%29+%2A+%28%28%28sqrt+%283%29%29%2F2%29%2A+a%5E2%2Ab%29

%28-21ab+%2B+b%29+%2A+%28%281.73%2F2%29%2A+a%5E2%2Ab%29
b%28-21a+%2B+1%29%2A+0.865%2A+a%5E2%2Ab%29
0.865a%5E2b%5E2%28-21a+%2B+1%29
now, if you set it equal to zero, you can calculate the values of a and b
0.865a%5E2b%5E2%28-21a+%2B+1%29=0
if 0.865a%5E2b%5E2=0 ...->...a=0 and b=0
if %28-21a+%2B+1%29=0 ...->...1=21a->...1%2F21=a



Probability-and-statistics/655216: Construct a scatterplot for the (x, y) values below, and answer the following questions. You needn’t submit your scatterplot with your answer.

x y
1 4
2 6
3 8
4 10
5 11







- Based on the scatterplot, would the correlation between x and y be positive or negative?
- How would you interpret these data in terms of linear regression? Please be sure to see the model in problem 6 of practice items posted in the P&S area
Could you please show work

1 solutions

Answer 408995 by MathLover1(6625) About Me  on 2012-09-22 00:03:02 (Show Source):
You can put this solution on YOUR website!

x | y
1 | 4
2 | 6
3 | 8
4 | 10
5 | 11
slope%28m%29=+%28y2-y1%29%2F%28x2-x1%29.... find the slope
slope%28m%29=%286-4%29%2F%282-1%29=+3%2F1=3
find the equation:
Solved by pluggable solver: FIND a line by slope and one point

What we know about the line whose equation we are trying to find out:

  • it goes through point (1, 4)

  • it has a slope of 3



First, let's draw a diagram of the coordinate system with point (1, 4) plotted with a little blue dot:



Write this down: the formula for the equation, given point x%5B1%5D%2C+y%5B1%5D and intercept a, is

y=ax+%2B+%28y%5B1%5D-a%2Ax%5B1%5D%29 (see a paragraph below explaining why this formula is correct)

Given that a=3, and system%28+x%5B1%5D+=+1%2C+y%5B1%5D+=+4+%29+, we have the equation of the line:

y=3%2Ax+%2B+1

Explanation: Why did we use formula y=ax+%2B+%28y%5B1%5D+-+a%2Ax%5B1%5D%29 ? Explanation goes here. We are trying to find equation y=ax+b. The value of slope (a) is already given to us. We need to find b. If a point (x%5B1%5D, y%5B1%5D) lies on the line, it means that it satisfies the equation of the line. So, our equation holds for (x%5B1%5D, y%5B1%5D): y%5B1%5D+=+a%2Ax%5B1%5D%2Bb Here, we know a, x%5B1%5D, and y%5B1%5D, and do not know b. It is easy to find out: b=y%5B1%5D-a%2Ax%5B1%5D. So, then, the equation of the line is: +y=ax%2B%28y%5B1%5D-a%2Ax%5B1%5D%29+.

Here's the graph:





Correlation: positive since as x rises, y rises




Rational-functions/655221: How do I determine f(-20) from a graph?
1 solutions

Answer 408978 by MathLover1(6625) About Me  on 2012-09-21 23:35:10 (Show Source):
You can put this solution on YOUR website!

+f%28-20%29 tells you that x=-20

construct a vertical line at x=-20 and see where it meets the graph


Radicals/655220: Square root (8x+1) =5
Please show work on how to solve for x
1 solutions

Answer 408974 by MathLover1(6625) About Me  on 2012-09-21 23:33:07 (Show Source):
You can put this solution on YOUR website!

+sqrt%288x%2B1%29+=5.......raise both sides to power of 2

+%28sqrt%288x%2B1%29%29%5E2+=5%5E2

+8x%2B1+=25

+8x=25-1

+8x=24

+x=24%2F8

+highlight%28x=3%29






Reduction-of-unit-multipliers/655201: How do you solve
2(v-8)+3(9-v)=3

-2(k-3) = k-5
1 solutions

Answer 408973 by MathLover1(6625) About Me  on 2012-09-21 22:47:53 (Show Source):
You can put this solution on YOUR website!

2%28v-8%29%2B3%289-v%29=3...first multiply
2v-16%2B27-3v=3
11-v=3
11-3=v
8=v


-2%28k-3%29+=+k-5
-2k%2B6+=+k-5
5%2B6+=2k%2B+k
11+=3k
11%2F3+=k
3.67+=k


Numeric_Fractions/655188: -8c^-3 divided by 2c^4
1 solutions

Answer 408972 by MathLover1(6625) About Me  on 2012-09-21 22:40:33 (Show Source):


Functions/655172: f(x)= 4|x-4|
Increasing? Decreasing? Constant? On?
1 solutions

Answer 408971 by MathLover1(6625) About Me  on 2012-09-21 21:53:04 (Show Source):
You can put this solution on YOUR website!
f%28x%29=4abs%28x-4%29
assuming x is real:
f%28x%29=4sqrt%28abs%28x-4%29%29%5E2
global minimum: min{.f%28x%29=4abs%28x-4%29.} is at x=4

+graph%28+500%2C+500%2C+-15%2C+25%2C+-15%2C+25%2C+4abs%28x-4%29%29+
Increasing? Decreasing? Constant? On?
(-infinity%29, 4]
Thus function is decreasing on this interval in its domain.

[4, infinity)
Thus function is increasing on this interval in its domain.
The function is continuous on its entire domain (-infinity,infinity)


Volume/655154: Find the outside surface area. Note that the container may not have a top. Assume a = 4 in., b = 5 in

http://www.webassign.net/smithnm11/9-3-041combo_6alt.gif
1 solutions

Answer 408964 by MathLover1(6625) About Me  on 2012-09-21 20:00:42 (Show Source):
You can put this solution on YOUR website!
since you have square pyramid (and assume a = 4 in, b = 5 in) which is a container that may not have a top, means you will not need the area of the base a%5E2=4%5E2=16
so, you will calculate lateral area:
L+=+4+%2A+%281%2F2%29a%2As+=+2a%2As+
L+=+4+%2A+%281%2F2%29%2A4in%2A5in
L+=++2%2A4%2A5in%5E2
L+=+highlight%2840in%5E2%29
if you include base area of a square pyramid (square):
+B+=+a%5E2
+B+=+%284in%29%5E2
+B+=+16in%5E2

you will have:
Total Surface Area of a square pyramid:
A+=+L+%2B+B+=40in%5E2%2B16in%5E2
+highlight%28A+=56in%5E2%29



Conjunction/655143: construct a truth table for ~(p v q)↔ (~p ^ ~q)

1 solutions

Answer 408958 by MathLover1(6625) About Me  on 2012-09-21 18:10:46 (Show Source):
You can put this solution on YOUR website!
click on this link and you will see your solution:

W3C Web site