Question

Which is a zero of quadratic function f(x)=9x^2-54x-19?

X= 1/3

X= 3 1/3

X= 6 1/3

X= 9 1/3

Answer 1

9x^2 - 54x - 19
= 9x^2 + 3x - 57x - 19
= 3x(3x + 1) - 19(3x + 1)
= (3x - 19)(3x + 1) = 0

x = -1/3, 19/3 (= 6 1/3 )

Answer is choice 3:-   6 1/3