Question

Нужна помощь врешении

Answer 1

Объяснение:

$a)4x - y = 9 \\ 3x + 7 = - 1 \\ \\ y = 4x - 9\\ 3x = - 8 \\ \\ y = - \frac{4 \times 8}{3} - 9\\ x = - \frac{8}{3} \\ \\ y = - \frac{32}{3} - 9\\ x = - 2 \frac{2}{3} \\ \\ y = - 19 \frac{2}{3} \\ x = - 2 \frac{2}{3} \\ \\ b)3x - y = 7 \\ 2x + 3y = 1 \\ \\ y = 3x - 7 \\ 2x + 3(3x - 7) = 1 \\ \\ y = 3x - 7 \\ 2 + 9x - 21 = 1 \\ \\ y = 3x - 7 \\ 9x = 20 \\ \\ y = 3 \times \frac{20}{9} - 7 \\ x = \frac{20}{9} \\ \\ y = \frac{20}{3} - 7 \\ x = 2 \frac{2}{9} \\ \\ y = - \frac{1}{3} \\ x = 2 \frac{2}{9}$