Question

пжжжжжжжжжжжжжж 7класс​

Answer 1

2.

$\frac{ {y}^{2} - 6y + 9 }{ {y}^{2} - 9 } \div \frac{10y - 30}{ {y}^{2} + 3y } = \frac{(y - 3) {}^{2} }{(y - 3)(y + 3)} \times \frac{y(y + 3)}{10(y - 3)} = \\ = \frac{y}{10} = \frac{70}{10} = 7$

3.

а)

$\frac{12x - 7}{15x} + \frac{3x - 2}{15x} = \frac{12x - 7 + 3x - 2}{15x} = \frac{15x -9 }{15x} = \\ = \frac{3(5x - 3)}{15x} = \frac{5x - 3}{5x}$

б)

$( \frac{3 {a}^{3} }{8 {b}^{2} } ) {}^{2} = \frac{ {3}^{2} {a}^{3 \times 2} }{ {8}^{2} {b}^{2 \times 2} } = \frac{9 {a}^{6} }{64 {b}^{4} }$