SOLUTION: I'm trying to solve an algebra problem and the examples in the book are very confusing. I need to use the substitution method. x-y=5 x+2y=7 If you could just show me the wo

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Question 487670: I'm trying to solve an algebra problem and the examples in the book are very confusing.
I need to use the substitution method.
x-y=5
x+2y=7
If you could just show me the work to reach the solution, I think I can do the rest of the problem?

Answer by ankor@dixie-net.com(22740)   (Show Source): You can put this solution on YOUR website!
use the substitution method.
x - y = 5
x + 2y = 7
Choose which equation you are going to use to substitute, we will choose the 1st one
x - y = 5
add y to both sides
x = (y + 5)
:
now on the 2nd equation we can substitute (y+5) for x
x + 2y = 7
substitute
(y+5) + 2y = 7
subtract 5 from both sides
y + 2y = 7 - 5
3y = 2
Divide both sides by 3
y =
:
Find x:
we know that x = y + 5
x = + 5
x = 5
:
Check solutions in the 2nd equation
x + 2y = 7
5 + 2() = 7
5 + = 7
5 + 1 = 7; confirms our solution



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