Решение уравнений

1. a) $$\frac{5}{6}x = 30$$ $$ x = 30 \cdot \frac{6}{5} $$ $$ x = \frac{30 \cdot 6}{5} = \frac{180}{5} = 36 $$ Ответ: x = 36
2. б) $$7x + 63{,}7 = 0$$ $$ 7x = -63{,}7 $$ $$ x = \frac{-63{,}7}{7} = -9{,}1 $$ Ответ: x = -9,1
3. в) $$4(0{,}8x + 2{,}35) - 1{,}4 = 2{,}8x$$ $$ 3{,}2x + 9{,}4 - 1{,}4 = 2{,}8x $$ $$ 3{,}2x - 2{,}8x = 1{,}4 - 9{,}4 $$ $$ 0{,}4x = -8 $$ $$ x = \frac{-8}{0{,}4} = -20 $$ Ответ: x = -20