SOLUTION: What is the ordered pair that is the solution to the system of equations: y = -2/3x x + 4y = 15

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Question 14183: What is the ordered pair that is the solution to the system of equations:

y = -2/3x
x + 4y = 15
Answer by Alwayscheerful(414) About Me  (Show Source):
You can put this solution on YOUR website!
you have 2 choices to solve this equation. 1. substitution 2. graphing
SUBSTITUTION
y=-2%2F3x
4y=-x%2B15
Plug in Y in the second equation
4%28-2%2F3x%29=-x%2B15
-8%2F3x%29=-x%2B15
isolate the X value
-5%2F3x=15
solve for x by multiplying both sides by -3/5 (the reciprocol)
x=15%2A%28-3%2F5%29
X=-9
Now plug X back in the original equation.
y=%28-2%2F3%29%2A-9
y=6
your ordered pair would be (-9, 6)
GRAPHING
convert both equations into y=mx+b form
you already have one:
y=-2x%2F3
You can convert by making the "y" stand by itself
4y=-x%2B15
divide both sides by 4
y=-1x%2F4%2B15%2F4
Then graph them.
graph%28+300%2C+200%2C+-10%2C+10%2C+-10%2C+10%2C+-2x%2F3%2C+-1x%2F4%2B15%2F4%29
Then you can either tell the intersection point on a graph of the two lines, or you can substitute.