Question

Варіант 1
4х +13+x+1= 3x +12​

Answer 1

$4x + 13 + x + 1 = 3x + 12 \\ 5x + 14 = 3x + 12 \\ 5x - 3x = 12 - 14 \\ 2x = - 2 \\ x = - 1$