Solve -x^2-9x-20=0 with the quadratic formula
plz help!

Answer:
a = -1 b = -9 c = -20
x1 = [--9 +- (sq root -9^2 - 4 * -1 * -20)] / 2 * -1
x1 = 9 +sq root (81 - 80) / -2
x1 = [9 + 1 ] / -2
x1 = -5
x2 = 9 -sq root (81 - 80) / -2
x2 = 8 / -2
x2 = -4
Step-by-step explanation: