Question

If 18 is subtracted from twice the square of an integer, the

result is equal to nine times the integer. Find the integer.
[Only an algebraic solution will be accepted.]

Answer 1

-3/2

Explanation:

Let x = the integer:

2x^2 - 18 = 9x

2x^2 - 9x - 18 = 0

Now either factor that or use the quadratic formula if you're lazy like me.

x = -3/2 and 6, so x must be 6 because it has to be an integer.