Question

Hello people ~factorise↷ x^2 + 4x –21​

Answer 1

Let's see

$\\ \rm\rightarrowtail x^2+4x-21$

$\\ \rm\rightarrowtail x^2+7x-3x-21$

$\\ \rm\rightarrowtail x(x+7)-3(x+7)$

$\\ \rm\rightarrowtail (x-3)(x+7)$