Question

Помогите решить 2x-3(7-2x)=3, 30-x=3(20-x)
-y+8-14y=23

Answer 1

$2x - 3(7 - 2x) = 3 \\ 2x - 21 + 6x = 3 \\ 8x - 21 = 3 \\ 8x - 21 + 21 = 3 + 21 \\ 8x = 3 + 21 \\ 8x = 24 \div 8 \\ x = 3 \\ \\ 30 - x = 3(20 - x) \\ 30 - x = 60 - 3x \\ - x + 3x = 60 - 30 \\ - x + 3x \\ - 1x + 3x \\ ( - 1 + 3)x = 2x \\ 2x = 30 \div 2 \\ x = 15 \\ \\ - y + 8 - 14y = 23 \\ - 15y + 8 = 23 \\ - 15y + 8 - 8 = 23 - 8 \\ - 15y = 23 - 8 \\ - 15y = 15 \div - 15 \\ y = - 1.$