Question

Решите уравнение: 1)2,5(4-2x)-5(1-3x)=5; 2)2/3(3x-1)-1/9(9x-2 1/4)=1/4; 3)-(x-5)-1,2(5-4x)=2,8; 4)-1 1/3(x-3)-2/3(x+1,5)=5.

Answer 1

$1)10 - 5x - 5 + 15x = 5 \\ 5 + 10x = 5 \\ 10x = 5 - 5 = 0 \\ x = 0 \div 10 = 0$

$2)2x - \frac{2}{3} - x + \frac{1}{4} = \frac{1}{4} \\ - \frac{2}{3} + \frac{1}{4} = - \frac{8}{12} + \frac{3}{12} = - \frac{5}{12}$

$x - \frac{5}{12} = \frac{1}{4} \\ x =\frac{1}{4}+\frac{5}{12}= \frac{3}{12}+\frac{5}{12}= \frac{8}{12}$

$= \frac{2}{3}$

$3) - x + 5 - 6 + 4.8x = 2.8 \\ 3.8x - 1 = 2.8 \\ 3.8x = 2.8 + 1 = 3.8 \\ x = 3.8 \div 3.8 = 1$

$- 1 \frac{1}{3}x + 4 - \frac{2}{3}x - 1 = 5 \\ - 2x + 3 = 5 \\ - 2x = 5 - 3 = 2 \\ x = 2 \div ( - 2) = - 1$
4)-1 1/3х+4-2/3х-1=5
-2х+3=5
-2х=5-3=2
х=2:(-2)=-1