Question

Answer Please.....
(3x+7)^2-84x=(3x-7)^2

Answer 1

$(3x) ^{2} + (7) ^{2} + 2(3x)(7) - 84x = (3x)^{2} + (7) ^{2} - 2(3x)(7) \\ 9x^{2} + 49 + 42x - 84x = 9x ^{2} + 49x - 42x \\ 9x ^{2} + 49x - 42x = 9x ^{2} + 49x - 42x \: \\ LHS=RHS$

Answer 2

3x^2+7x^2+2×3x ×7-84x = 3x^2+7x^2-2×3x×7
9x^2+49x^2+42x-84 x= 9x^2+49x^2-42x
9x^2+49x^2-42 = 9x^2+49 x^2-42x
verified