Question 184870
If you subtract a number from its square, the result is 12. Find all such numbers
:
x^2 - x = 12
;
x^2 - x - 12 = 0
factor
(x-4)(x+3) = 0 
Two solutions
x = +4
and 
x = -3
:
Check the 2nd solution
(-3)^2 - (-3) = 12
9 + 3 = 12