Question 1029278
Let us call it x.  Then we write
x*x + 3x = 180
Now let's solve it, remembering that we want the negative value for x...
x^2 + 3x - 180 = 0
Now factor it...
(x + 15)(x - 12) = 0
so that
x = -15  or x = 12
So we want the negative one, so
Derrick's integer is -15.