values of x

Question

Select the approximate values of x that are solutions to f(x) = 0, where
f(x) = -6x2 + 4x + 3.

 

These are the answers I have to choose from
{–2.00, 1.33}

{-6, 4}

{–0.67, –0.50}

{–0.45, 1.12}

Answer 1

Hi Shawna,

 

To find the zeros of your function you might first try to factor. However, this quadratic doesn't factor, so you have to solve another way. If you're comfortable with the method of completing the square, that will work. The fastest way to do this, though, is by using the quadratic formula. Your solutions will be

 

x = [-b ± √(b² - 4ac)] / 2a

 

where a, b, and c are the coefficients of your function in the form

f(x) = ax² + bx + c

 

In this case,

a = -6

b = 4

c = 3

 

Plug these numbers into the quadratic equation, and use your calculator to find the value of your zeros. You get one answer when you use the + in the numerator, and a 2nd answer when you use the -.