Question

пожалуйста решите тольок б)
и в) ​

Answer 1

б) ответ: –10

$7( \frac{2}{7} x - \frac{3}{14} y) - 4( \frac{7}{2} x - \frac{3}{8} y) = \frac{7 \times 2}{7} x - \frac{7 \times 3}{14} y - \frac{4 \times 7}{2} x + \frac{4 \times 3}{8} y = 2x - \frac{3}{2} y - 14x + \frac{3}{2} y = - 12x$

$x = \frac{5}{6} , y = 1$

$- 12 \times \frac{5}{6} = - \frac{12 \times 5}{6} = - 10$

в) ответ: 0

$2(4a - 0.5b) - (3a - 7b) = 8a - b - 3a + 7b = 5a + 6b$

$a = - 0.4, b = \frac{1}{3}$

$5 \times ( - 0.4) + 6 \times \frac{1}{3} = - 2 + \frac{6}{3} = - 2 + 2 = 0$

Answer 2

б) 7(2/7х - 3/14у) - 4(7/2х-3/8) = 2х - 1 1/2у - 14х + 1 1/2у = 2х - 14х - 1 1/2у + 1 1/2у = - 12х = -12 • 5/6 = -10
в) 2(4а - 0,5b) - (3a - 7b) = 8a - b - 3a + 7b = 8a - 3a - b + 7b = 5a + 6b = 5 • (-0,4) + 6 • 1/3 = - 2 + 2 = 0