Question

Сократить дробь!Помогите)

Answer 1

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

Answer 2

[(3x+7)²-(3x-7)²]/x=(3x+7-3x+7)(3x+7+3x-7)/x=14*6x/x=84