Question

дам 80 баллов :) можете только 1)номер решать или все​

Answer 1

Объяснение:

1.

а)

$0.5x(x - 3) = 0.6(4 + x) - 2.6 \\ 0.5x - 1.5 = 2.4 + 0.6x - 2.6 \\ 0.5x - 1.5 = - 0.2 + 0.6x \\ 0.5x - 0.6x = - 0.2 + 1.5 \\ - 0.1x = 1.3 \\ x = - 13$

б)

$4(0.2x - 7) - 5(0.3x + 6) = 5 \\ 0.8x - 28 - 1.5x - 30 = 5 \\ - 0.7x - 58 = 5 \\ - 0.7x - = 58 + 5 \\ - 0.7x = 63 \\ x = \frac{63}{ - 0.7} = - \frac{630}{7} = - 90 \\ x = - 90$

в)

$(5x - 7) \times (2x - 0.4) = 0 \\ \\ 5x - 7 = 0 \\ 2x - 0.4 = 0 \\ \\ x1 = \frac{7}{5} \\ x2 = \frac{0.4}{2} = \frac{1}{5}$

г)

$\frac{x - 4.1}{2.5} = \frac{x + 0.8}{5} \\ \frac{2(x - 4.1)}{5} = \frac{x + 0.8}{5} \\ 2x - 8.2 = x + 0.8 \\ 2x - x = 0.8 + 8.2 \\ x = 9$

2.

$( - 3.9 \times 2.8 + 26.6) \div ( - 3.2) - 2.1 \\ ( - 10.92 + 26.6) \div ( - 3.2 ) - 2.1 \\ 15.68 \div ( - 3.2) - 2.1 \\ - 4.9 - 2.1 = - 7$