(3x-4)(3x-4) ??? You have to times each of the numbers from the opposite brackets together :) 3x x 3x = 9x^2 3x x -4 = -12x -4 x 3x = -12x -4 x -4 = 16 (a minus times a minus is a plus)
So it's 9x^2 -12x -12x +16 Which can be simplified to... 9x^2 -24x +16