Question

Find the zeros of the following polynomial. Enter your answers below in a

Round to three decimal places when necessary. Hint: Factor by grouping.
5x³ +9x² - 45x-81=0
=

Answer 1

-3 ; -9/5 ; 3

Explanation:

5x³ - 45x + 9x² - 81 = 0

5x (x²-9) + 9(x²-9) = 0

(x²-9)(5x+9) = 0

x²-9 = 0

x² = 9

x = +√9 = 3

x = -√9 = -3

5x+9 = 0

5x = -9

5/5 x = -9/5

x = -9/5