TMEtienne 1 year, 5 months ago 9x^2-81 This question was asked about: Pg. 328, Algebra 2 abdo 1 year, 5 months ago 0 9x^2-81=(3x)^2-9^2=(3x-9)(3x+9) 9x^2-81=(3x)^2-9^2=(3x-9)(3x+9) submit cancel 0 comments Add a Comment cancel Add an Answer submit cancel