Question 358019
X(X+1)=X+X+1+11
X^2+X=2X+12
X^2+X-2X-12=0
X62-X-12=0
(X-4)(X+3)=0
X-4=0
X=4 ANS.
4+1=5 ANS.
PROOF:
4*5=4+5+11
20=20