Question

Помогите 4 и 6!!!!!!

Answer 1

4.
$a) \: \: \frac{1}{3} {b}^{3} \times 3( - b) = - {b}^{4} \\ b) \: \: 2 {x}^{2} \frac{7}{x} = 14x$
6.
$\sqrt{x} > 0 \\ \sqrt{x} = 2 \\ x = 4$
[0;4) и (4;. + бесконечность)