Question

40 баллов, задание на фото.

Answer 1

Ответ:

$1) - 7 + 3y = 18 \\ 3y = 18 + 7 \\ 3y = 25 \\ y = \frac{25}{7} \\ y = 8 \frac{1}{3}$

$2) - 19 = 7x + 12 \\ - 7x = 12 + 19 \\ - 7x = 31 \\ x = - \frac{31}{7} \\ x = - 4 \frac{ 3}{7}$

$3)4( - 3 + x) = 3x + 88 \\ - 12 + 4x = 3x + 88 \\ 4x - 3x = 88 + 12 \\ x = 100$

$4)18 - 2x = 7x - 18 \\ - 2x - 7x = - 18 - 18 \\ -9x = - 36 \\ x = \frac{ - 36}{ - 9} \\ x = 4$

$5)105 - 7x = 42 \\ - 7x = 42 - 105 \\ - 7x = - 63 \\ x = \frac{ - 63}{ - 7 } \\ x = 9$

$6)1.78x + 0.84 = 1.34 - 0.72x \\ 1.78x + 0.72x = 1.34 - 0.84 \\ 2.5x = 0.5 \\ x = \frac{0.5}{2.5} \\ x = 0.2$

$7)9(2x - 3) = 3(3x - 10) \\ 18x - 27 = 9x - 30 \\ 18x - 9x = - 30 + 27 \\ 9x = - 3 \\ x = \frac{ - 3}{9} \\ x = - \frac{1}{3}$