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josmiceli answered: 9646 problems
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Inequalities/532706: In which inequality is m = 10 a solution?
3m(m - 3) > 360
3m(m - 3) > 420
3m(m + 3) < 420
3m(m + 3) < 360

1 solutions

Answer 350907 by josmiceli(9649) About Me  on 2011-11-16 14:59:35 (Show Source):
You can put this solution on YOUR website!
Number 3, +3m%2A%28m+%2B+3%29+%3C+420+
is correct. The rest are false.
proof:
+3%2A10%2A%2810+%2B+3%29+%3C+420+
+30%2A13+%3C+420+
+390+%3C+420+


Linear-systems/532313: A basketball player makes a total of 517 shots totaling 1037 points. How many of those shots are 3 point shots and how many are 2 point shots?
From the examples in the book, I should have 2 equations:
x + y = 517
2x + 3y = 1037
Is this right?
How do I begin to solve?
1 solutions

Answer 350800 by josmiceli(9649) About Me  on 2011-11-15 20:34:40 (Show Source):
You can put this solution on YOUR website!
That's right.
+x+ = number of 2 point shots
+y+ = number of 3 point shots
(1) +x+%2B+y+=+517+
(2) +2x+%2B+3y+=+1037+
Multiply both sides of (1) by 2 and
subtract (1) from (2)
(2) +2x+%2B+3y+=+1037+
(1) +-2x+-+2y+=+-1034+
+y+=+3+
and, since
(1) +x+%2B+y+=+517+
(1) ++x+=+517+-+3+
(1) +x+=+514+
The shots are 514 two point shots and 3 three point shots
check:
(2) +2x+%2B+3y+=+1037+
(2) +2%2A514+%2B+3%2A3+=+1037+
(2) +1028+%2B+9+=+1037+
(2) +1037+=+1037+
OK


Systems-of-equations/532301: Automotive maintenance. The radiator in Natalie’s car contains 6.3 L of antifreeze and water. This mixture is 30% antifreeze. How much of this mixture should she drain and replace with pure antifreeze so that there will be a mixture of 50% antifreeze?
1 solutions

Answer 350793 by josmiceli(9649) About Me  on 2011-11-15 20:24:16 (Show Source):
You can put this solution on YOUR website!
Let x = liters of mixture she should
drain and replace with pure antifreeze
-----------
given:
+.3x+ = liters of pure antifreeze that
she drains off
+.3%2A%28+6.3+-+x+%29+ = pure antifreeze left after
she drains off +x+ liters of mixture
-----------
+%28+.3%2A%28+6.3+-+x+%29+%2B+x+%29+%2F+6.3+=+.5+
+%28+1.89+-+.3x+%2B+x+%29+%2F+6.3+=+.5+
+1.89+%2B+.7x+=+.5%2A+6.3+
+.7x+=+3.15+-+1.89+
+.7x+=+1.26+
+x+=+1.8+
She must drain off 1.8 liters and replace with pure antifreeze
check:
+%28+.3%2A%28+6.3+-+x+%29+%2B+x+%29+%2F+6.3+=+.5+
+%28+.3%2A%28+6.3+-+1.8+%29+%2B+1.8+%29+%2F+6.3+=+.5+
+%28+.3%2A4.5+%2B+1.8+%29+%2F+6.3+=+.5+%7D%7D%0D%0A%7B%7B%7B++1.35+%2B+1.8++=+.5%2A6.3+
+3.15+=+3.15+
OK


Numbers_Word_Problems/532287: Mr. Wilhems got $2 discount on the purchase of 5 bags of peat moss. If he paid $7.40, what was the price for one bag of peat moss before discount?? Please help me!? Thanks(:
1 solutions

Answer 350778 by josmiceli(9649) About Me  on 2011-11-15 20:08:01 (Show Source):
You can put this solution on YOUR website!
Let +x+ = the original price of 5 bags of peat moss
given:
+x+-+2+=+7.4+
+x+=+9.4+
+9.4%2F5+=+1.88+
The cost of 1 bag before discount was $1.88


Linear-equations/532263: Felisa jogged 3 miles in 25 minutes and then jogged 3 more miles in 30 minutes. What was her average speed in miles per minute?
1 solutions

Answer 350754 by josmiceli(9649) About Me  on 2011-11-15 19:36:38 (Show Source):
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Ave speed = ( total miles ) / ( total time )
Ave speed = +%28+3+%2B+3+%29+%2F+%28+25+%2B+30+%29+
Ave speed = +6%2F55+ mi/min


Mixture_Word_Problems/532246: The manager of a coffee shop has one type of coffee that sells for $8 per pound and another that sells for $15 per pound. The manager wishes to mix 60 pounds of the $15 coffee to get a mixture that will sell for $14 per pound. How many pounds of the $8 coffee should be used?
1 solutions

Answer 350747 by josmiceli(9649) About Me  on 2011-11-15 19:32:04 (Show Source):
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Let +x+ = pounds of $8 coffee needed
given:
+60%2A15+=+900+ is cost of $15 coffee
+8x+ = cost of $8 coffee
+60+%2B+x+ = total pounds of coffee in mixture
-----------
+%28+900+%2B+8x+%29+%2F+%28+60+%2B+x+%29+=+14+
+900+%2B+8x+=+14%2A%28+60+%2B+x+%29+
+900+%2B+8x+=+840+%2B+14x+
+6x+=+900+-+840+
+6x+=+60+
+x+=+10+
10 pounds of $8 coffee are needed
check:
+%28+900+%2B+8x+%29+%2F+%28+60+%2B+x+%29+=+14+
+%28+900+%2B+8%2A10+%29+%2F+%28+60+%2B+10+%29+=+14+
+980+%2F+70+=+14+
+980+=+80+
OK


Radicals/531817: Question is
"Write an equivalent expression using radical notation"
(Simplify, type an integer if applies)
625^ 3/4
625 to the 3-4th exponent
Thank you very much!
1 solutions

Answer 350619 by josmiceli(9649) About Me  on 2011-11-15 05:02:07 (Show Source):
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Note that +625+=+5%5E4+, so
+%28+625+%29%5E%281%2F4%29+=+5+, so
+%28+625+%29%5E%283%2F4%29+=+5%5E3+
+5%5E3+=+125+
------------
In case this isn't what they want,
+%28625%29%5E%283%2F4%29+=+root%28+4%2C%28625%29%5E3%29+


Permutations/531828: no. of ways a lawn tennis mixed doubles can be made up from 7 married couples if no husband and wife play in same set
1 solutions

Answer 350618 by josmiceli(9649) About Me  on 2011-11-15 04:53:04 (Show Source):
You can put this solution on YOUR website!
Here's my try.
You should get another opinion, too
-----------
One of the male players has 7 women he can choose
as a partner, minus his wife = 6
The number of possible pairs is 7*6
-----------
The other male player is one of the 6 remaining, and
he can choose one of 6 remaining women, minus his wife = 5
The number of possible pairs is 6*5.
-----------
The number of possible matches is 7*6*6*5 = 1260


Percentage-and-ratio-word-problems/531759: If there are 20 foxes in the forest this year, and 21 in one year, what percent is the percent growth of the foxes?
1 solutions

Answer 350598 by josmiceli(9649) About Me  on 2011-11-14 22:28:59 (Show Source):
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The increase is 1, and there were 20 to start with
+1%2F20+=+5%2F100+
+5%2F100+=+.05+
The percent growth is 5%


Proportions/531727: Barbara's goal is to practice piano 20 minutes for every 5 minutes of lessons she takes. If she takes a 20 minute piano lesson this week, how many minutes should she practice this week?
1 solutions

Answer 350586 by josmiceli(9649) About Me  on 2011-11-14 21:43:33 (Show Source):
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( min of practice ) / ( min of lesson ) the goal
equals ( min of practice ) / ( min of lesson ) this week
+20%2F5+=+x%2F20+
Multiply both sides by 20
+80+=+x+
She should practice 80 min this week


Rectangles/531717: The length of a rectangular piece of carpet is 5 meters less than twice its width.
Find dimensions of the carpet if its area is 33 square meters.
1 solutions

Answer 350583 by josmiceli(9649) About Me  on 2011-11-14 21:38:18 (Show Source):
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(1) +L+=+2W+-+5+
+A+=+33+
+L%2AW+=+33+
(2) +W+=+33%2FL+
Substitute (2) into (1)
(1) +L+=+2%2A%2833%2FL%29+-+5+
(1) +L%5E2+=+66+-+5L+
(1) +L%5E2+%2B+5L+-+66+=+0+
Use quadratic formula
L+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
+a+=+1+
+b+=+5+
+c+=+-66+
L+=+%28-5+%2B-+sqrt%28+5%5E2-4%2A1%2A%28-66%29+%29%29%2F%282%2A1%29+
L+=+%28-5+%2B-+sqrt%28+25+%2B+264+%29%29%2F2+
L+=+%28-5+%2B-+sqrt%28+289+%29%29%2F2+
L+=+%28-5+%2B+17%29%2F2+
+L+=+12%2F2+
+L+=+6+ ( ignore the negative root )
(2) +W+=+33%2FL+
(2) +W+=+33%2F6+
(2) +W+=+5.5+
The dimensions are 5.5 m x 6 m
check:
(1) +L+=+2%2A%2833%2FL%29+-+5+
(1) +6+=+2W+-+5+
(1) +6+=+2%2A5.5+-+5+
(1) +6+=+11+-+5+
(1) +6+=+6+
OK


Polynomials-and-rational-expressions/531151: How do you factor 4x^2 + 9x + 2
NOTE: the ^2 is a exponent, not sure how else to write them here.
1 solutions

Answer 350359 by josmiceli(9649) About Me  on 2011-11-13 23:39:26 (Show Source):
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+4x%5E2+%2B+9x+%2B+2+
Use quadratic formula
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
+a+=+4+
+b+=+9+
+c+=+2+
x+=+%28-9+%2B-+sqrt%28+9%5E2-4%2A4%2A2+%29%29%2F%282%2A4%29+
x+=+%28+-9+%2B-+sqrt%28+81+-+32+%29%29+%2F+8+
x+=+%28+-9+%2B-+sqrt%28+49+%29%29+%2F+8+
x+=+%28+-9+%2B+7%29+%2F+8+
+x+=+-2%2F8+
+x+=+-1%2F4+
and
x+=+%28+-9+-+7%29+%2F+8+
+x+=+-2+
The factors are:
+%28+x+%2B+1%2F4+%29%2A%28+x+%2B+2+%29+=+4x%5E2+%2B+9x+%2B+2+


Equations/531141: Translate the following statement to mathematical symbols:
Francisco weighs twenty pounds more than Skyler does.
If Skyler weighs one hundred forty pounds, how much does Francisco weigh?
Francisco is pounds.
1 solutions

Answer 350358 by josmiceli(9649) About Me  on 2011-11-13 23:29:27 (Show Source):
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F = S + 20
S = 140
F = 140 + 20
F = 160


absolute-value/531142: Parking garage fees the Greenville City Garage charges $5 for the first hour and then $2.75 for each additional hour. How long has a car been parked at this garage if the parking chare is $29.75?
1 solutions

Answer 350357 by josmiceli(9649) About Me  on 2011-11-13 23:25:23 (Show Source):
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Let t = length of time in hours
that car has been parked
given:
+2975+=+500+%2B+%28+t+-+1+%29%2A275+ ( in cents )
+2975+=+500+%2B+275t+-+275+
+275t+=+2975+-+500+%2B+275+
+275t+=+2750+
+t+=+10+
They've been parked 10 hrs


Functions/531147: If gloria received a 6% raise and is now making 22,260 a year, what was her salary before the raise?
1 solutions

Answer 350356 by josmiceli(9649) About Me  on 2011-11-13 23:14:01 (Show Source):
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Let x = her salary before the raise
given:
+x+%2B+.06x+=+22260+
+1.06x+=+22260+
+x+=+22260%2F1%2F06+
+x+=+21000+
her salary was $21,000


Quadratic_Equations/530867: If the vertex of a parabola is (-1,-7) how can I find the equation of the parabola? Is this possible?
1 solutions

Answer 350229 by josmiceli(9649) About Me  on 2011-11-13 16:11:45 (Show Source):
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Not quite, the x-coordinate of the vertex is
+-b%2F%282a%29+ when the general formula
for the equation is +y+=+ax%5E2+%2B+bx+%2B+c+
So I have:
+-b%2F%282a%29+=+-1+
+b+=+2a+
the y coordinate is +-7+, so
+-7+=+a%2Ax%5E2+%2B+2a%2Ax+%2B+c+
+a%2Ax%5E2+%2B+2a%2Ax+%2B+c+%2B+7+=+0+
I can still only get a formula for the roots in terms
of a and c, so there can be many equations
that have (-1,-7) for a vertex


Numbers_Word_Problems/530862: find two consecutive odd integers such that the sum of four times the larger, and 7 more than the smaller is equal to 50
1 solutions

Answer 350223 by josmiceli(9649) About Me  on 2011-11-13 16:02:20 (Show Source):
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Call the numbers n and +n%2B2
given:
+4%2A%28n+%2B+2%29+%2B+n+%2B+7++=+50+
+4n+%2B+8+%2B+n+%2B+7+=+50+
+5n+%2B+15+=+50+
+5n+=+50+-+15+
+5n+=+35+
+n+=+7+
+n+%2B+2+=+9+
The numbers are 7 and 9
check:
+4%2A%287+%2B+2%29+%2B+7+%2B+7++=+50+
+4%2A9+%2B+14+=+50+
+36+%2B+14+=+50+
+50+=+50+
OK


Linear-equations/530828: a line passing through (0,6) and (2,1) can i get a step by step in words not numbers please.
1 solutions

Answer 350214 by josmiceli(9649) About Me  on 2011-11-13 15:39:32 (Show Source):
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What is the equation of the line passing through
(0,6) and (2,1) ?
the point-slope formula says:
( change in y ) / ( change in x ) = ( change in y ) / ( change in x )
Suppose I call the 2 given points +P%5B1%5D+, and +P%5B2%5D+
+P%5B1%5D+ = (x1 , y1)
+P%5B2%5D+ = (x2 , y2)
Change in y = y2 - y1
Change in x = x2 - x1
-----------------
The formula uses the concept that any point (x,y) is also
OK to use, so I can say
( change in y ) / ( change in x ) = ( y - y1 ) / ( x - x1 )
-----------------
Putting these ideas together,
( y - y1 ) / ( x - x1 ) = ( y2 - y1 ) / ( x2 - x1 )
Now you just have to substitute the actual numbers:
(x1,y1) = (0,6)
(x2,y2) = (2,1)
+%28+y+-+6+%29+%2F+%28+x+-+0+%29+=+%28+1+-+6+%29+%2F+%28++2+-+0+%29+
+%28+y+-+6+%29+%2F+x+=+-5%2F2+
+y+-+6+=+%28-5%2F2%29%2Ax+
+y+=+%28-5%2F2%29%2Ax+%2B+6+
check answer:
(2,1)
+1+=+%28-5%2F2%29%2A2+%2B+6+
+1+=+-5+%2B+6+
+1+=+1+
OK


Proportions/530523: a giraffe can run 32mph. what is this speed in feet per second? round your answer to the nearest tenth.
1 solutions

Answer 350144 by josmiceli(9649) About Me  on 2011-11-12 21:25:14 (Show Source):
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(32 miles/hr) x ( 1 hr/3600 sec ) x ( 5280 ft/1 mile ) =
+%2832%2A5280%29%2F3600+ ft/sec
+46.933+ ft/sec


Quadratic_Equations/530526: For the quadratic equation +2x%5E2%2B2x%2B3=0+, explain how to find a value of "b" where the discriminant yields a quadratic equation with the following types of solutions.
a. two imaginary solutions
b. one real solution
c. two rational solutions
d. two irrational solutions
1 solutions

Answer 350125 by josmiceli(9649) About Me  on 2011-11-12 20:54:21 (Show Source):
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The discriminant is +b%5E2+-+4%2Aa%2Ac+
where +y+=+ax%5E2+%2B+bx+%2B+c+
In the quadratic formula, it appears
under the square root sign
(1)
2 imaginary solutions:
+b%5E2+%3C+4%2Aa%2Ac+
(2)
1 real solution:
+b%5E2+=+4%2Aa%2Ac+
(3)
2 rational solutions:
+b%5E2+%3E+4%2Aa%2Ac+
and
+b%5E2+-+4%2Aa%2Ac+ is a perfect square
(4)
+b%5E2+%3E+4%2Aa%2Ac+
and
+b%5E2+-+4%2Aa%2Ac+ is not a perfect square


logarithm/530537: For what value of x is it true that (log x)^3 = 3 log x?
1 solutions

Answer 350113 by josmiceli(9649) About Me  on 2011-11-12 20:39:59 (Show Source):


Functions/530490: what is a rule for the function repersented by (o,-2),(1,-1),(2,2),(3,7)? Explain your reasoning.
1 solutions

Answer 350081 by josmiceli(9649) About Me  on 2011-11-12 18:34:07 (Show Source):
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It's not a straight line, so I'ii assume it's a
2nd degree equation in the form
+y+=+ax%5E2+%2B+bx+%2B+c+
(0,-2)
+-2+=+0+%2B+0+%2B+c+
+c+=+-2+
(1,-1)
+-1+=+a+%2B+b+-2+
+a+%2B+b+=+1+
+b+=+1+-+a+
(2,2)
+2+=+4a+%2B+2b+-+2+
+4a+%2B+2b+=+4+
+2a+%2B+b+=+2+
by substitution:
+2a+%2B+1+-+a+=+2+
+a+=+1+
+b+=+0+
The equation so far is
+y+=+x%5E2+-+2+ answer
Does it go through (3,7) ?
+7+=+9+-+2+ yes


Travel_Word_Problems/530487: Tyrone can paint a kitchen in 7 hours, and Shauna can paint the same kitchen in 6 hours. How long would it take for both working together to paint the kitchen? (you can leave your answer as an improper fraction or a mixed number).
1 solutions

Answer 350077 by josmiceli(9649) About Me  on 2011-11-12 18:13:38 (Show Source):
You can put this solution on YOUR website!
Add their rates of painting
Tyrone's rate: ( 1 kitchen )/(7 hrs)
Shauna's rate: ( 1 kitchen )/(6 hrs)
Rare together: ( 1 kitchen )/(t hrs)
+1%2F7+%2B+1%2F6+=+1%2Ft+
Multiply both sides by +42t+
+6t+%2B+7t+=+42+
+13t+=+42+
+t+=+42%2F13+ hrs


Mixture_Word_Problems/530254: A chemist wants to make a 45% solution of Sulfuric Acid more concentrated by addingpure sulfuric acid. How much pure sulfuric acid must be added to get an 80% solution of sulfuric acid?
1 solutions

Answer 349975 by josmiceli(9649) About Me  on 2011-11-11 23:39:07 (Show Source):
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Let +1+ = unit of sulfuric acid solution originally
Let +x+ units of pure sulfuric acid to be added
given:
+.45+ = units of sulfuric acid originally
---------
+%28+.45+%2B+x+%29+%2F+%28+1+%2B+x+%29+=+.8+
+.45+%2B+x+=+.8%2A%28+1+%2B+x+%29+
+.45+%2B+x+=+.8+%2B+.8x+
+.2x+=+.8+-+.45+
+.2x+=+.35+
+x+=+1.75+
The ratio of pure acid to be added to solution already present
must be 1.75/1 or 7/4


Money_Word_Problems/530163: SUPPOSE THAT YOU JUST RECEIVED AN EMAIL
ALERT FROM A WEBSITE INDICATING THAT 4-GIGABYTE FLASH
DRIVES HAVE JUST BEEN DISCOUNTED BY 60%. IF THE
SALE PRICE OF THE FLASH DRIVE IS NOW $11.80, WHAT
WAS THE ORIGINAL PRICE?
1 solutions

Answer 349916 by josmiceli(9649) About Me  on 2011-11-11 18:24:18 (Show Source):
You can put this solution on YOUR website!
Let +x+ = the original price
given:
+x+-+.6x+=+11.8+
+.4x+=+11.8+
+x+=+11.8%2F.4+
+x+=+29.5+
The original price was $29.50


Permutations/530164: For a party, a person sets up 6 card tables and pushes them together in a row. How many people can be seated at the arrangement? (Note: Only one person can sit on each side of a card table.)
Please show your work, thank you!
Allen~
Chicago, IL
1 solutions

Answer 349915 by josmiceli(9649) About Me  on 2011-11-11 18:19:06 (Show Source):
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3 people can sit at the card tables at both ends
That makes 6 people
There are 4 tables left, and only 2 people can
sit at these tables
That makes 8 more people
+6+%2B+8+=+14+
14 people can be seated


Age_Word_Problems/529992: seven years ago B was twice as young as A,when A was3 years younger than B is now. How old is A now?
1 solutions

Answer 349843 by josmiceli(9649) About Me  on 2011-11-11 09:25:09 (Show Source):
You can put this solution on YOUR website!
Let a = A's age now
Let b = B's age now
+a+-+7+ = A's age 7 years ago
+b+-+7+ = B's age 7 years ago
---------------------------
given:
7 years ago, A was 3 years younger than B is now
(1) +a+-+7+=+b+-+3+
7 years ago, B was twice as young as A ( half A's age )
(2) +b+-+7+=+%281%2F2%29%2A%28a+-+7%29+
---------------------
(2) +2%2A%28b+-+7%29+=+a+-+7+
(2) +2b+-+14+=+a+-+7+
(2) +a+-+2b+=+-7+
and
(1) +a+-+7+=+b+-+3+
(1) +a+-+b+=+4+
(1) +-b+=+-a+%2B+4+
(1) +b+=+a+-+4+
Substitute (1) into (2)
(2) +a+-2%2A%28a+-+4%29+=+-7+
(2) +a+-+2a+%2B+8+=+-7+
(2) +-a+=+-15+
(2) +a+=+15+
A is 15
check:
(1) +b+=+a+-+4+
(1) +b+=+15+-+4+
(1) +b+=+11+
(2) +b+-+7+=+%281%2F2%29%2A%28a+-+7%29+
(2) +11+-+7+=+%281%2F2%29%2A%2815+-+7%29+
(2) +4+=+%281%2F2%29%2A8+
(2) +4+=+4+
OK


Expressions-with-variables/529990: (7+2x) (7-2x)=
1 solutions

Answer 349842 by josmiceli(9649) About Me  on 2011-11-11 09:08:07 (Show Source):


Travel_Word_Problems/529981: are (2,9) and (-3,-6) both on the line y = 4x+ 6 ?
if not find an equation for the line that pass through both points
1 solutions

Answer 349841 by josmiceli(9649) About Me  on 2011-11-11 09:04:14 (Show Source):
You can put this solution on YOUR website!
Only (-3,-6) is on the line because
+-6+=+4%2A%28-3%29+%2B+6+
+-6+=+-12+%2B+6+
+-6+=+-6+
(2,9) is not on the line because
+9+=+4%2A2+%2B+6+
+9+=+8+%2B+6+
+9+=+14+ not true
------------------
Use point-slope formula:
+%28y+-+%28-6%29%29+%2F+%28x+-%28-3%29%29+=+%289+-+%28-6%29%29+%2F+%282+-+%28-3%29%29+
+%28y+%2B+6%29+%2F+%28x+%2B+3%29+=+%289+%2B+6%29+%2F+%282+%2B+3%29+
+%28y+%2B+6%29+%2F+%28x+%2B+3%29+=+15+%2F+5+
+%28y+%2B+6%29+%2F+%28x+%2B+3%29+=+3+
+y+%2B+6+=+3%2A%28x+%2B+3%29+
+y+%2B+6+=+3x+%2B+9+
+y+=+3x+%2B+3+ answer
check:
(-3,-6)
+-6+=+3%2A%28-3%29+%2B+3+
+-6+=+-9+%2B+3+
+-6+=+-6+
OK
(2,9)
+9+=+3%2A2+%2B+3+
+9+=+6+%2B+3+
+9+=+9+
OK


real-numbers/529845: A dehydrated patient needs a 3.24% saline IV. Unfortunately, the hospital only has bags of 1% and 9%saline solution. How many liters of each of these solutions should be mixed together to yield 5 liters of the desired concentration?
1 solutions

Answer 349777 by josmiceli(9649) About Me  on 2011-11-10 21:37:27 (Show Source):
You can put this solution on YOUR website!
Let a = liters of 1% solution needed
Let b = liters of 9% solution needed
given:
(1) +a+%2B+b+=+5+ liters
(2) +%28.01a+%2B+.09b%29+%2F+5+=+.0324+
---------------------------
(2) +%28.01a+%2B+.09b%29+%2F+5+=+.0324+
(2) +%28.01a+%2B+.09b%29++=+.0324%2A5+
(2) +.01a+%2B+.09b+=+.162+
(2) +a+%2B+9b+=+16.2+
Subtract (1) from (2)
(2) +a+%2B+9b+=+16.2+
(1) +-a+-+b+=+-5+
+8b+=+11.2+
+b+=+1.4+
and, since
(1) +a+%2B+b+=+5+
(1) +a+%2B+1.4+=+5+
(1) +a+=+3.6+
3.6 liters of 1% solution are needed
1.4 liters of 9% solution are needed
check:
(2) +%28.01%2A3.6+%2B+.09%2A1.4%29+%2F+5+=+.0324+
(2) +%28+.036+%2B+.126+%29+%2F+5+=+.0324+
(2) +.162+=+5%2A.0324+
(2) +.162+=+.162+
OK


Graphs/529863: Could you please help me solve this equation with SUBSITUTION:
Y=-4x
Y=2x-3
I need to show my work.
1 solutions

Answer 349776 by josmiceli(9649) About Me  on 2011-11-10 21:22:58 (Show Source):
You can put this solution on YOUR website!
(1) +y+=+-4x+
(2) +y+=+2x+-+3+
Substitute y in (1) for y in (2)
(2) +-4x+=+2x+-+3+
Add +4x+ to both sides
(2) +0+=+6x+-+3+
Add 3 to both sides
(2) +3+=+6x+
Divide both sides by 6
(2) +x+=+3%2F6+
(2) +x+=+1%2F2+