Respuesta :
Use distributive property: a(b +/- c) = ab +/ ac.
(x - 9)(x + 2) = (x)(x) + (x)(2) - (9)(x) - (9)(2) = x² + 2x - 9x - 18
= x² -7x -18
(x - 9)(x + 2) = (x)(x) + (x)(2) - (9)(x) - (9)(2) = x² + 2x - 9x - 18
= x² -7x -18