g(x) = 5x^2 - 4x, h(x) = -4x^2 - 6x

Question

I need to find  (g - h)(3). I am confused on how to do this. Please help!

Answer 1

Hello, thank you for taking the time to post your question!

(g – h)(3) means finding g(x) – h(x) in functional form, then plugging in x = 3 to evaluate

For this one that means taking

5x^2 – 4x – (-4x^2 – 6x)

=5x^2 – 4x + 4x^2 + 6x

=9x^2 + 2x

Then when you plug in x = 3 that should be

9(3)^2 + 2(3)

=9(9) + 6

=81 + 6

=87

I hope that helps get you moving in the right direction! Feel free to reach out if you have any additional questions beyond that :)

Answer 2

g(x) - h(x) = 5x² - 4x - (-4x² -6x) = 5x² - 4x + 4x² + 6x = 9x² + 2x

 

(g-h) (3) = 9(3)² + 2(3) = 9(9) + 6  = 81 + 6 = 87