Q4 of 83 Page 76

(x — 7)2 — 16 = 0

(x — 7)2 — 42 = 0


Using the identity (a + b)(a – b) = a2 – b2


Where a = (x – 7) and b = 4


⇒ (x – 7 + 4)(x – 7 – 4) = 0


⇒ (x – 3)(x – 11) = 0


⇒ x – 3 = 0 or x – 11 = 0


Therefore x = 3 and x = 11


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