(х+1)² - (х-2)(х+4) = х² + 2х + 1 - (х² + 4х - 2х - 8) = х² + 2х + 1 - (х² + 2х - 8) = х² + 2х + 1 - х² - 2х + 8 = 2х + 9
(х+1)² - (х-2)(х+4) = х² + 2х + 1 - (х² + 4х - 2х - 8)
= х² + 2х + 1 - (х² + 2х - 8)
= х² + 2х + 1 - х² - 2х + 8
= 2х + 9