Question

consider the graph of the function y=1/4x2-3x-40. what are the roots of the function?

Answer 1

Answer: the roots are x = 20 and x = -8

Step-by-step explanation:

We have the function

y = (1/4)x^2 - 3x - 40

We want to find the roots, that are the points in where y(x) = 0

For a quadratic equation of the form:

y = a*x^2 + bx + c the roots are:

$x = \frac{-b +-\sqrt{b^2 -4*a*c} }{2*a}$

in this case we have:

$x = \frac{3 +-\sqrt{3^2 +4*(1/4)*40} }{2*(1/4)}= \frac{3 +-7}{(1/2)}$

So the two roots are:

x = 2*(3 + 7) = 20

x = 2*(3 - 7) = -8