Question

Simplify: a. (x²+xy) (x² - xy)
b. (3x + 7)² - (3x -7)²​

Answer 1

a) (x^2+xy)(x^2-xy)

a^2-b^2

(x^2)^2-(xy)^2

x^4-x^2y^2

b) (3x+7)^2-(3x-7)^2

3x^2+7^2+2×3x×7 - (3x^2+7^2-2×3x×7){by a+b)^2 and (a-b)^2

9x^2+49+42x - 9x^2-49+42x

84x

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