2) \: 2x + y = 18 \\ y = 18 - 2x \\
3) \: - 0.2k = 8 \\ k + m = - 1 \\ \\ k = - 40 \\ - 40 + m = - 1 \\ \\ - 40 + m = - 1 \\ m = - 1 + 40 \\ m = 39 \\
Ответ : k = -40 ; m=39
\\ \\ 4) \: x - y = 0 \\ x = \frac{1}{9} \\ \\ \frac{1}{9} - y = 0 \\ y = \frac{1}{9} - 0 \\ y = \frac{1}{9}
\\ Ответ : х = 1/9 ; у = 1/9" alt="1) \: 2a + 7b = 20 \\ 2a = 20 - 7b \\ a = \frac{20 - 7b}{2} \\ a = 10 - 3.5b \\
2) \: 2x + y = 18 \\ y = 18 - 2x \\
3) \: - 0.2k = 8 \\ k + m = - 1 \\ \\ k = - 40 \\ - 40 + m = - 1 \\ \\ - 40 + m = - 1 \\ m = - 1 + 40 \\ m = 39 \\
Ответ : k = -40 ; m=39
\\ \\ 4) \: x - y = 0 \\ x = \frac{1}{9} \\ \\ \frac{1}{9} - y = 0 \\ y = \frac{1}{9} - 0 \\ y = \frac{1}{9}
\\ Ответ : х = 1/9 ; у = 1/9" align="absmiddle" class="latex-formula">