Question 324461
X=3Y+4
XY=7
(3Y+4)Y=7
3Y^2+4Y=7
3Y^2+4Y-7=0
(3Y+7)(Y-1)=0
Y-1=0
Y=1 ANS.
X=3*1+4
X=3+4=7 ANS.
PROOF:
7*1=7
7=7