Question

Find all the zeros of the quadratic function.

Answer 1

...coefficients: a=1 ; b=-1 ; c=-20

Δ=b²−4ac=(-1)²-4(1*-20)=81

Δ is strictly positive, so the equation x²-x-20=0 has two solutions.

(-b-√Δ)/2a =(1-9)/2=-4

(-b+√Δ)/2a = (1+9)/2=5

solutions to the quadratic equation x²-x-20 = 0 :

x = 5 and x = -4.