Question

Решите уравнения:
а) $3*(0,4x + 1,4) = x - 0,8$
б)$3x + 1 \frac{2}{9} = x - 3 \frac{10}{27}$

Answer 1

3*(0.4x  + 1.4) = x - 0.8
1.2x + 4.2 = x - 0.8
1.2x - x = -0.8 - 4.2
0.2x  = -5
x = -5 / 0.2
x = -25
=======
3x + 1  2/9 = x - 3 10/27 | * 27
27 * 3x + 11/9 * 27 = 27* x  - 91/27 * 27 
81x + 33 = 27x - 91
81x - 27x = -91 - 33
54x = -124
x = -124 / 54
x = - 2   16/54
x = - 2   8/27

Answer 2

$3(0.4x + 1.4) = x - 0.8 \\\ 1.2x + 4.2 = x - 0.8 \\\ 1.2x-x = - 0.8-4.2 \\\ 0.2x= - 5 \\\ x=- \frac{5}{0.2} \\\ x=-25$

$3x + 1 \frac{2}{9} = x - 3 \frac{10}{27} \\\ 3x -x= - 3 \frac{10}{27} - 1 \frac{2}{9} \\\ 2x= - \frac{91}{27} - \frac{33}{27} \\\ 2x= - \frac{91+33}{27} \\\ 2x= - \frac{124}{27} \\\ x= - \frac{124}{2\cdot27} \\\ x= - \frac{62}{27} \\\ x= -2 \frac{8}{27}$