№ 2. Решите уравнение: 1) 2x = 18-x; 2) 7x + 3 = 30 - 2x; 3) 7 - 2x = 3x – 18; 4) 0,2x + 2,7 = 1,4-1,1x

1) $$2x + x = 18 \implies 3x = 18 \implies x = 6$$.
2) $$7x + 2x = 30 - 3 \implies 9x = 27 \implies x = 3$$.
3) $$7 + 18 = 3x + 2x \implies 25 = 5x \implies x = 5$$.
4) $$0.2x + 1.1x = 1.4 - 2.7 \implies 1.3x = -1.3 \implies x = -1$$.