Question

$factorise:{a}^{2} {b }^{2} - 4$
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Answer 1

Answer:

(ab+2)(ab-2)

Step-by-step explanation:

$a^{2} .b^{2} - 4$

= $(ab)^{2} -2^{2}$

= (ab+2)(ab-2)    (using formula $a^{2} - b^{2} = (a+b)(a-b)$ )