SOLUTION: how do you use elimination to solve for the x and the y 11x - 5y = 80 9x - 15y = 120

Algebra ->  Expressions-with-variables -> SOLUTION: how do you use elimination to solve for the x and the y 11x - 5y = 80 9x - 15y = 120      Log On


   

Question 5256: how do you use elimination to solve for the x and the y
11x - 5y = 80
9x - 15y = 120
Answer by xcentaur(357) About Me  (Show Source):
You can put this solution on YOUR website!
9x - 15y = 120
3x - 5y = 40
y=(40-3x)/-5


Substituting this value of y in eqn1,we have eliminated variable y from the first equation


11x - 5y = 80
11x - 5(40-3x)/-5 = 80
multiplying through out by '-5'
-55x - 5(40-3x) = -400
dividing throughout by '-5'
11x +(40-3x) = 80
11x-3x=80-40
8x=40
x=5


y=(40-3x)/-5
=(40-15)/-5
=25/-5
=-5


x=5,y=-5

Hope this helps,good luck.