Question

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(2a − 3b + 5c)²

Answer 1

(2a − 3b + 5c)²

Here, let a = 2a, b = −3b, c = 5c

Using the identity,

(a + b + c)² = a² + b² + c² + 2ab + 2bc + 2ca

Thus,

(2a − 3b + 5c)² = (2a)² + (−3b)² + (5c)² + 2(2a) (−3b) + 2(−3b)(5c) + 2(5c) (2a)

= 4a² + 9b² + 25c² + 2(−6ab) + 2(−15bc) + 2(10ac)

∴ (2a − 3b + 5c)² = 4a² + 9b² + 25c² − 12ab − 30bc + 20ac