How do you factor $ab + ac - 4b - 4c$ ?

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Answer 1 · 2015-11-27T03:40:08

$color(blue)((a-4)(b+c)$ is the factorised form of the expression.

$ab +ac -4b-4c$

We can make groups of two to factorise this expression:

$color(blue)((ab +ac)) color(green)((-4b-4c)$

$a$ is common to both the terms in the first group, and $-4$ is common to both the terms in the second group.

$=color(blue)(a)(b +c) color(green)(-4)(b+c)$

The term $(b+c)$ is common to both the terms:

$color(blue)((a-4)(b+c)$ is the factorised form of the expression.

How do you factor ab + ac - 4b - 4cab + ac - 4b - 4c?