# College Math

I need help solving these problems by using the substitution problem
2x-3y=16
5x+2y=21

1. 0
asked by Cam
1. substitution is a method, not a problem (though it appears to be a problem for you! :-)

taking the first equation, solve for x or y:

x = (16+3y)/2

now "substitute" that into the other equation

5(16+3y)/2 + 2y = 21
80+15y + 4y = 42
19y = -38
y = -2
so, x = (16-6)/2 = 5

check that (5,-2) fits both original equations, just to be sure

posted by Steve

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