Question

ПОМОГИТЕ решить способом подстановки х через у ДАЮ 40 БАЛОВ​

Answer 1

а)

$u + \frac{1}{3} (u + v - 3) = 14 \: \: \: | \times 3 \\ \frac{1}{3} v - \frac{1}{6} (u + v) = \frac{5}{6} \: \: \: | \times 6 \\ \\ 3u + u + v - 3 = 42 \\ 2v - u - v = 5 \\ \\ 4u + v = 45 \\ - u + v = 5 \\ \\ 4u + 5 + u = 45 \\ v = 5 + u \\ \\ 5u + 5 = 45\\ 5u = 45 - 5 \\ 5u = 40 \\ u = 40 \div 5 \\ u = 8 \\ \\ v = 5 + 8 = 13$

Ответ: u = 8 ; v = 13

б)

$7(2x + y) - 5(3x + y) = 6 \\ 3(x + 2y) - 2(x + 3y) = - 6 \\ \\ 14x + 7y - 15x - 5y = 6 \\ 3x + 6y - 2x- 6y = - 6 \\ \\ - x + 2y = 6 \\ x = - 6 \\ \\ - ( - 6) + 2y = 6 \\ 6 + 2y = 6 \\ 2y = 6 - 6 \\ 2y = 0 \\ y = 0$

Ответ: ( - 6 ; 0 )