Question

Show that
a) (3x + 7)? - 84x =(3x - 7)?
b) (a - b)(a + b) + (b-c)(b + c) = (a - c)(a + c)​

Answer 1

Step-by-step explanation:

a) (3x+7)? -84x=(3x-7)?

LHS. = RHS

LHS,

(3x)² + (7)² + 2 × 3x × 7 -84x

9x² + 49 + 42x - 84x (42x-84x)

9x² + 49 - 42x

RHS,

(3x)² + (7)² - 2 × 3x × 7

9x² + 49 - 42x

Therefore, LHS = RHS

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