Question 152194
Let the number = x
x+x^2=12(x+1)
x+x^2=12x+12
x^2-11x-12=0
(x-12)(x+1)=0
x=12 or x=-1
.
Check:
12+144=12*13 True
-1+(-1)^2=12*0 True
.
Ed