19+ x = 4(x−3)+7

$$\begin{aligned} &19+ x = 4(x-3)+7 \\ &19 + x = 4x - 12 + 7 \\ &19 + x = 4x - 5 \\ &19 + 5 = 4x - x \\ &24 = 3x \\ &x = \frac{24}{3} \\ &x = 8 \end{aligned}$$ Ответ: x = 8