SOLUTION: how do i sove this problem (step by step) x-y=5 x+2y=7

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Question 137848This question is from textbook prentice hall algebra 1
: how do i sove this problem (step by step)
x-y=5 x+2y=7 This question is from textbook prentice hall algebra 1

Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
1.x-y=5
2.x%2B2y=7
There are many ways to solve this system of linear equations.
I'll use the substitution method.
Use equation 1, to solve for x in terms of y.
1.x-y=5
x=y%2B5
Now use this value and substitute for x in equation 2.
2.x%2B2y=7
%28y%2B5%29%2B2y=7
3y%2B5=7
Now solve for y.
3y=2
y=2%2F3
You can work backwards and find x now that you have y.
x=y%2B5
x=%282%2F3%29%2B5
x=%282%2F3%29%2B%2815%2F3%29
x=17%2F3
Always check your answers.
Use your original equations.
1.x-y=5
%2817%2F3%29-%282%2F3%29=5
15%2F3=5
5=5
True statement.
Good answer.
2.x%2B2y=7
%2817%2F3%29%2B2%282%2F3%29=7
%2817%2F3%29%2B%284%2F3%29=7
21%2F3=7
7=7
True statement.
Good answer.
x=17%2F3
y=2%2F3