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Question
Factorise the following algebraic expression by using the identity a2 – b2 = (a + b)(a – b)
z2 – 16
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Solution
z2 – 16 = z2 – 42
We have a2 – b2 = (a + b)(a – b)
let a = z and b = 4,
z2 – 42 = (z + 4)(z – 4)
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