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Recent problems solved by 'tutorcecilia'
tutorcecilia answered: 2149 problems
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graph the equations
y=3x
y=x+3 1 solutions
Answer 59539 by tutorcecilia(2152) on 2007-05-22 10:14:22 (Show Source):
You can put this solution on YOUR website!y=3x
or
y=3x+0
Compared to the equation of a line formula:
y=mx+b
y=any y value
m=the slope of the line
x=any corresponding x-value
b=the point where the line intersects the y-axis
For y=3x+0,
the line will cross or intersect the y=axis at (0, 0), starting from that point, use the slope of 3 or 3/1. That is, from (0, 0,) go up +3 and over +1 and plot that point (1,3)
From (1, 3) go up +3 and over +1 and plot that point (2, 6).
.
Now for the bottom of the graph, start again at (0, 0), and using the slope
-3/-1 (same as +3), go down -3 and to the left (-1); plot this point (-1, -3).
Repeat this pattern by going down -3 and over to the left -1; plot this point (-2, -6).
.
Connect the lines.
.
y=x+3
or y=1x+3
The slope = 1 or 1/1
The line crosses or intersects the y-axis at (0, 3)
So, repeat the instructions from above, only start at point (0, 3) and go up 1 and over 1, etc.
Graphing:
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Graphs/82790: Solve 3(x-5)+3x=4x+5 1 solutions
Answer 59438 by tutorcecilia(2152) on 2007-05-21 14:32:53 (Show Source):
You can put this solution on YOUR website!3(x-5)+3x=4x+5
3x-15+3x=4x+5
6x-15=4x+5
6x-4x-15=4x-4x+5
2x-15=5
2x-15+15=5+15
2x=20
2x/2=20/2
x=10
.
check by plugging (x=10) back into the original equation and solve:
3(10-5)+3x=4x+5
3(5)+3(10)=4(10)+5
15+30=40+5
45=45 [checks out]
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Coordinate-system/82844: This one really confused me - please help!
Write the equation of the line that satisfies the given condition: contains the point (2,6) and is perpendicular to the line 4x-5y=7.
Thank you! 1 solutions
Answer 59422 by tutorcecilia(2152) on 2007-05-21 13:52:13 (Show Source):
You can put this solution on YOUR website!Lines that are perpendicular have slopes that are the negative reciprocal of each other:
For example:
if slope #1 = 2, then the perpendicular slope = -1/2
.
Line #1
4x-5y=7 [re-write in the y=mx+b format]
4x-4x-5y=-4x+7
-5y=-4x+7
-5y/-5=-4/-5x+7/-5
y=4/5x-7/5
Slope # 1 = 4/5
.
So, slope of Line #2 =-5/4 [because I flipped 4/5 and multiplied it by (-1)]
y=mx+b [plug-in the values (2, 6) and (m=-5/4) and solve for the b-term]
6=(-5/4)(2)+b
6=-5/2+b
5/2+6=b
17/2=b
Plug-in just the values of the slope and the b-term:
y=-5/4x+17/2
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Linear-equations/82836: Identify the slope of each direct variation
1. a. y = 7x b.y= -3x c. y= x d. y= 1/2x
e. y= -1.4x f.y= 2.673x g. y= 3 2/3x h. y= -8x 1 solutions
Answer 59419 by tutorcecilia(2152) on 2007-05-21 13:19:13 (Show Source):
You can put this solution on YOUR website!Use the formula y=mx+b where the m-term represents the value of the slope
.
1.
a. y = 7x
Slope = 7
.
b.y= -3x
Slope = m=-3
.
c. y= x
Slope=m=1
.
d. y= 1/2x
Slope=m=1/2
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Proportions/82838: Multiply to find the missing value. Include units in your answer.
3. a.72 hr * $4/1 hr
b. 55 mi/1 hr * 7 hr/1 day
c. 35 people/1 party * 2.5 pizzas/10 people 1 solutions
Answer 59417 by tutorcecilia(2152) on 2007-05-21 13:16:43 (Show Source):
You can put this solution on YOUR website!3.
a.  [cancel out the hour units; the dollar units are left]
.
$288/1 [multiply straight across
$288
.
b.  [convert days to hours]
[cancel out the units wherever possible (hours and days cancel out]
.
 [you are left with miles/hour]
16.0416 mi/hr [multiply straight across]
.
c. 35 people/1 party * 2.5 pizzas/10 people [cancel units wherever possible (people units)]
.
35 /1 party * 2.5 pizzas/10
35 people/1 party * 2.5 pizzas/10 people
8.75 pizzas/party [multiply straight across]
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Graphs/82568: Determine which two equations represent parallel lines:
(a)y=-9x+4
(b)y=9x+4
(c)y=1/9x+4
(d)y=-9+5 1 solutions
Answer 59173 by tutorcecilia(2152) on 2007-05-18 13:48:01 (Show Source):
You can put this solution on YOUR website!Lines that are parallel have the same slope. In the y=mx+b formula, the "m" is the slope. So look at each equation and find matching slopes:
(a)and (d) have matching slopes, so these two lines are parallel.
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Quadratic_Equations/82523: Solve the system by addition or substitution.
–6x + 3y = 12
y = 2x + 3
1 solutions
Answer 59169 by tutorcecilia(2152) on 2007-05-18 13:18:05 (Show Source):
You can put this solution on YOUR website!–6x + 3y = 12 [re=write]
-6x+6x+3y=6x+12
3y=6x+12
3y/3=6x/3+12/3
y=2x+4
.
y=2x+4
y=2x+3
______
.
.
(-1)y=2x+4
y=2x+3
______
.
.
-y=-2=-4
y=2x+3
________
0y=0x+-1
o=-1 [untrue statement, so there is no solution or no points in common]
.
Also, note that the lines have the same slope (2), therefore the lines are parallel and will never intersect.
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Expressions-with-variables/82571: Solve the system by substitution:
2x+2y=0
y=4x+0 1 solutions
Answer 59165 by tutorcecilia(2152) on 2007-05-18 13:02:47 (Show Source):
You can put this solution on YOUR website!2x+2y=0 [substitute (y=4x+0) for the y-term and solve for the x-term]
.
2x+2(4x+0)=0
2x+2(4x)=0
2x+8x=0
10x=0
10x/10=0/10
x=0
.
solve for the y-term by plugging x=0 back into one of the original equations:
2x+2y=0
2(0)+2y=0
2y=0
2y/2=0/2
y=0
.
check by plugging the values for x and y back into either eiquation and solve:
2x+2y=0
2(0)+2(0)=0
0=0 [checks out].
and
y=4x+0
0=4(0)+0
0=0 [also checks out]
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Quadratic_Equations/82575: The length of a rectangle is 4 in. more than twice its width. If the perimeter of the rectangle is 56 in., find the width of the rectangle.
Answer: The width is ______
Show work:
1 solutions
Answer 59161 by tutorcecilia(2152) on 2007-05-18 12:45:13 (Show Source):
You can put this solution on YOUR website!Formula for the perimeeter of a rectangle:
P=2[(length + width)]
P=56
Length=2w+4
Width=w
.
so,
56=2[(2w+4)+w)]
56/2=2/2(2w+4+w)]
28=3w+4
28-4=3w
24=3w
24/3=3w/3
8=w
.
So,
P=56
Length=2w+4 = 2(8)+4=16+4=20
Width=w=8
.
Plugging everything back into the formula for a perimeter:
P=2[(length + width)]
56=2(20+8)
56=2(28)
56=56 [checks out]
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Equations/82585: I have to solve this: √x-1=x-3
This is what I have done so far. Am I on the right track? What do I do now?
"The radical symbol is only over the x-1"
√x-1=x-3
(√x-1)^2=(x-3)^2
x-1 = (x-3)(x-3)
x-1 = x^2-6x+9
x-1 = x^2-6x+9
0=x^2-7x+10
1 solutions
Answer 59160 by tutorcecilia(2152) on 2007-05-18 12:37:23 (Show Source):
You can put this solution on YOUR website!Good job!! I agree with your answer. You correctly initially squared both sides of the equation in order to get rid of the radical; used FOIL on the left side; and solved for the x-term.
.
If your instructor/book wanted you to solve for the x=term, just continue the process:
0=x^2-7x+10
(x-5)(x-2)=0
x-5=0
x=5
or x-2=0
x=2
.
Try plugging each x-value back into the original equation to make sure each solution is a true solution. One of the values of x could possibly be an erroneous solution:
.
 = 
Let x=5
 =
 =  [the square root of 4 is either a plus or minus 2]
2=2 [so, x=5 checks out]
.
 = 
Let x=2
 =  [the square root of 1 is either a plus or minus (1). In this case, the (-1) works]
-1 = -1 [ture, so x=2 is also a solution]
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Radicals/82584: I have to simplify this problem please help. Can anybody show me how to do equations like this one? The ones with letters and that are on top of each other are really hard.
√75a / √5 1 solutions
Answer 59158 by tutorcecilia(2152) on 2007-05-18 12:22:29 (Show Source):
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Linear-equations/82221: Please some assistance is needed.
Plot the point with coordinates (-3,-3) 1 solutions
Answer 58948 by tutorcecilia(2152) on 2007-05-16 14:15:19 (Show Source):
You can put this solution on YOUR website!Starting at the origin of (0,0) on the graph, go three spaces to the left (-3) and than down three spaces (-3). Plot the point.
.
For coordinate points, (x, y) the first number tells you how many spaces to move on the x-axis (left or right). The second number tells you how many spaces to move on the y-axis (up or down)
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Polynomials-and-rational-expressions/82235: This question is from textbook
please assist me with the following:
1.factor: y2-4y-5
2. factor 3a2+9a+6
3.evaluate: x(x+1)(x-1)
4.facctor: 6y2-2yz 1 solutions
Answer 58947 by tutorcecilia(2152) on 2007-05-16 14:11:10 (Show Source):
You can put this solution on YOUR website!1.factor: y2-4y-5
(y-5)(y+1)
.
2. factor 3a2+9a+6
(3a+3)(a+2)
.
3.evaluate: x(x+1)(x-1)
set each factor equal to zero and solve for the x-term:
x=0
x+1=0
x=-1
and x-1=0
x=1
So, x= 0, -1 and 1
.
4.factor: 6y2-2yz
factor out (2y)

(2y)(3y-z)
.
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Quadratic_Equations/82238: This question is from textbook
please assist me with the following:
1. factor 6f2+5f+1
2. factor 12w2+10w-8
3. factor: 20y2-33y+10
factor: -x2-x-6 1 solutions
Answer 58938 by tutorcecilia(2152) on 2007-05-16 13:26:34 (Show Source):
You can put this solution on YOUR website!1. factor 6f2+5f+1

(3f+1)(2f+1)=0 [use trial-and-error to find the factors that have a product (multiplied) of the first and last term; and a sum (add) of the middle term]
Example: factor  =(3f)(2f)
factor the last term of (1) = (1)(1)
Try to find the combination of the factors that, when added togeter, will equal the middle term of 5f.
(3f+1)(2f+1)
.
factor 12w2+10w-8

(6w+8)(2w-1) [use trial-and-error to find the factors that have a product (multiplied) of the first and last term; and a sum (add) of the middle term]
Example: 12 = (6)(2) or (12)(1) or (3)(4)
and -8 = (-1)(8) or (1)(-8) or (-4)(2) or (-2)(4)
Try to find the combinations that, when added, will equal the middle term of (10w)
.
3. factor: 20y2-33y+10

(5y-2)(4y-5)[use trial-and-error to find the factors that have a product (multiplied) of the first and last term; and a sum (add) of the middle term]
.
factor: -x2-x-6

(-x-3)(x-2)[use trial-and-error to find the factors that have a product (multiplied) of the first and last term; and a sum (add) of the middle term]
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Graphs/82257: how do I graph the inequality y<1? 1 solutions
Answer 58936 by tutorcecilia(2152) on 2007-05-16 12:53:59 (Show Source):
You can put this solution on YOUR website!y<1
First, establish a boundary line by using an equal sign:
y=1 (see the graph:

.
In this case, the boundary line will be a dashed line because the inequality is "less than" "1". If the inequality had been just "less than or equal to", the boundary line would have been a solid line instead.
.
Now, shade every thing below or less than the line (which is everything < 1) since "y" is every point less than the line (see the graph below):
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Rectangles/82261: The length of a rectangle is 3in more than twice its width. If the perimeter of the rectangle is 36in, find the width of the rectangle.
(a)7in
(b)6in
(c)4in
(d)5in 1 solutions
Answer 58928 by tutorcecilia(2152) on 2007-05-16 12:14:41 (Show Source):
You can put this solution on YOUR website!Use the formula for the perimeter of a rectangle:
P=2(length+width)
P=36
Length = 3in more than twice its width = 2 x Width +3 = 2w+3
Width=w
.
P=2(l+w) [plug-in the values and solve for the width(w)]
36=2[(2w+3)+w]
36/2=2/2(2x+3+w)
18=2w+3+w
18=3w+3
18-3=3w
15=3w
15/3=3w/3
5=w
.
checking:
Length = 2w+3=2(5)+3=13
Width=5
.
36=2(13+5)
36=2(18)
36=36 [checks out]
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