Question

итоговая контрольная работа по алгебре 7класс Колягин ,пожалуйста помогите

Answer 1

1.

$(2 \frac{2}{5} - 3.2) \times 3 \frac{3}{4} = ( \frac{12}{5} - \frac{32}{10} ) \times \frac{15}{4} = ( \frac{24}{10} - \frac{32}{10} ) \times \frac{15}{4} = - \frac{4}{5} \times \frac{15}{4} = - 3$

2.

$\frac{ {a}^{3} {a}^{5} }{ {( {a}^{2}) }^{3} } = \frac{ {a}^{8} }{ {a}^{6} } = {a}^{2} = {( - 2)}^{2} = 4$

3.

${a}^{3} {b}^{2} 5 {(b {a}^{2}) }^{3} = 5 {a}^{3} {b}^{2} \times {b}^{3} {a}^{6} = 5 {a}^{9} {b}^{5}$

4.

${(2x + 1)}^{2} - (2x + 3)(2x - 3) = 0 \\ \\ 4 {x}^{2} + 4x + 1 - 4 {x}^{2} + 9 = 0 \\ \\ 4x + 10 = 0 \\ \\ 4x = - 10 \\ \\ x = - \frac{5}{2} = - 2.5$