X+2y=7
3x-2y=-3 solving systems by substitution

Move 2y to the right hand side of the equation by subtracting 2y from both sides.
x=−2y+7 
3x−2y=−3

Replace all occurrences of x with the solution found by solving the last equation for x. In this case, the value substituted is −2y+7.
x=−2y+7 
3(−2y+7)−2y=−3

Simplify each term.
x=−2y+7 
−6y+21−2y=−3

Add −6y and −2y to get −8y.
x=−2y+7 
−8y+21=−3

Move 21 to the right hand side of the equation.
x=−2y+7 
−8y=−21−3

Subtract 3 from −21 to get −24.
x=−2y+7 
−8y=−24

Divide each term in the equation by −8.
x=−2y+7 
y=3

Replace all occurrences of y with the solution found by solving the last equation for y. In this case, the value substituted is 3.
x=−2(3)+7 
y=3

Multiply −2 by 3 to get −6.
x=−6+7 
y=3

Add −6 and 7 to get 1.
x=1 
y=3

(1,3)