Hello from MrBillDoesMath!
Answer:
x = 15 or x = -4
Discussion:
Start by factoring the given quadratic:
3x^2 - 33x - 180 = (factor 3 from each term)
3( x^2 - 11x - 60) = ( -15 + 4 = -11; (-15)*4 = -60)
3 (x -15)(x+4)
This equals zero when x = 15 or x = -4
Thank you,
MrB