Question 674719
x=y+12
xy=28 replace x by (y+12) in this equation.
(y+12)y=28
y^2+12y=28
y^2+12y-28=0
(y+14)(y-2)=0
y-2=0
y=2 ans.
x=2+12
x=14 ans.
Proof:
2*14=28
28=28