Помогите решить быстро и понятно

A) -2.7x = 256.68
x = -256.68 / 2.7
$x = -\frac{25668}{100} / \frac{27}{10} \\ \\ x = -\frac{25668}{100} * \frac{10}{27} \\ \\ x = -\frac{2852}{10} * \frac{1}{3} \\ \\ x = -\frac{1426}{5} * \frac{1}{3}\\ \\ x = - \frac{1426}{15} = -95\frac{1}{15} \\ \\ \\$
$b) (2,8 - y)*(-0,8) = \frac{12}{25} \\ \\ - 2,24 + 0,8y = \frac{4}{5}\\ \\ 0,8y = \frac{4}{5} + 2,24\\ \\ 0,8y = 0,8 + 2,24 \\ \\ 0.8y = 3.04 \\ \\y = 3.04 / 0.8 = 3.8$