Question

Match the following expressions with their factorised form.

• A. $(x+4)(x-4)$
• B. $(x+1{)}^2$
• C. $(x-6{)}^2$
• D. $(x-7)(x+7)$

Answer 1

The expressiom can be written as

$x^2-16$ =$x^2-4^2$ = $(x+4)(x-4)$ [a^2- b^2 = (a+b)(a-b)]
$x^2+2x+1$ = $(x+1{)}^2$ [(a+b)^2 = a^2 + b^2 + 2ab]
$x^2-12x+36$ = $(x-6{)}^2$ [(a-b)^2 = a^2 + b^2 - 2ab]
$x^2-49$ =$x^2-7^2$ = $(x+7)(x-7)$ [a^2- b^2 = (a+b)(a-b)]