Question 487670
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 = {{{2/3}}}
:
Find x:
we know that x = y + 5
x = {{{2/3}}} + 5
x = 5{{{2/3}}}
:
Check solutions in the 2nd equation
x + 2y = 7
5{{{2/3}}} + 2({{{2/3}}}) = 7
5{{{2/3}}} + {{{4/3}}} = 7
5{{{2/3}}} + 1{{{1/3}}} = 7; confirms our solution