Question 73894
X+Y=36
X=36-Y
X=3Y-4 THUS WE SUBSTITUTE (3Y-4) FOR X IN THE OTHER EQUATION & WE GET.
(3Y-4)=36-Y
3Y-4=36-Y
3Y+Y=36+4
4Y=40
Y=10 ANSWER NOW SUBSTITUTE 10 FOR Y & SOLVE FOR X
X+10=36
X=36-10
X=26 ANSWER.
PROOF
26=3*10-4
26=30-4
26=26