Question 348213
(x^2+9x)(x^2-9x) = 


USE THE FOIL METHOD.


x^2 * x^2 = x^4


x^2 * - 9x = -9x^3


9x * x^2 = 9x^3


9x * -9x = -81x^2


Put it all together and combine like terms.


x^4 - 9x^3 + 9x^3 - 81x^2


x^4 - 81x^2


We now factor.


x^2(x^2 - 81)


We now factor what lies in the parentheses.


Final Answer: x^2 (x - 9) (x + 9)