Question

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`(5a - b/2 + 4c)^2`

Answer 1

`(5a-b/2+4c)^2`

Here, let a = 5a, b = `-b/2`, c = 4c

Using the identity,

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

`(5a - b/2 + 4c)^2 = (5a)^2 + (-b/2)^2 + (4c)^2 + 2(5a)(-b/2) + 2(-b/2)(4c) + 2(4c)(5a)`

= `25a^2 + b^2/4 + 16c^2 + 2(-(5ab)/2) + (-(2b)/2)(4c) + 2(20ac)`

∴ `(5a-b/2 + 4c)^2 = 25a^2 + b^2/4 + 16c^2 -  5ab - 4bc + 40ac`