Question

Evaluate using suitableIdentities. 1. (2a + 7) (2a – 7)​

Answer 1

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Step-by-step explanation:

$(2a + 7)(2a - 7)$

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

$(2a + 7)(2a - 7) = (2a)^{2} - (7) ^{2}$

$4a ^{2} - 49$

Hope it helps

Answer 2

$\large\green{\textsf{✩ Verified Answer ✓ }}$

(2a + 7) (2a – 7) = (2a - 7)²

using identity,

(a - b) ² = a² - 2ab + b²

=> (2a - 7)² = (2a²) - 2 × 2a × 7 + 7²

=> (2a - 7)² = 4a² - 28a +49