SOLUTION: how do you verify that your solution is correct for this equation? x+y=20 x-y=4

Algebra ->  Absolute-value -> SOLUTION: how do you verify that your solution is correct for this equation? x+y=20 x-y=4      Log On


   

Question 775830: how do you verify that your solution is correct for this equation?
x+y=20
x-y=4
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

x%2By=20.......eq.1
x-y=4.....eq.2
______________________ first find solutions that make both equations true
x%2By=20.......eq.1
x-y=4.....eq.2
______________________...add eq.1 and eq.2
x%2By%2Bx-y=20%2B4
2x%2Bcross%28y%29-cross%28y%29=24
2x=24
x=24%2F2
highlight%28x=12%29
now find y
x%2By=20.......eq.1...plug in x=12
12%2By=20
y=20-12
highlight%28y=8%29
to verify that your solution is correct, go back to original equations and plug in values for x and y
x%2By=20.......eq.1
12%2B8=20
20=20
x-y=4.....eq.2
12-8=4
4=4........since the left side of the equation is same as the right side in both eq.1 and eq.2 means your solution is correct