Question

tìm x

1, \(0,4\cdot x-\frac{1}{5}x=\frac{3}{4}\)

2, \(x\div1\frac{2}{7}=-3,5\)\

3, \(\left(\frac{2x}{5}-2\right)\div\left(-5\right)=\frac{3}{7}\)

4, x+ 20% x = -4,8

5, \(x-15\%x=-2\frac{11}{20}\)

6, \(\left(x\cdot25\%-\frac{2}{3}\right)\div2\frac{1}{3}=1\frac{5}{8}\)

Answer 1

1. 0,4x - 1/5x = 3/4

=> 1/5x = 3/4

=> x = 3/4 : 1/5

=> x = 15/4

Answer 2

2.

x : 1 2/7 = -3,5

=> x = -3,5 . 9/7 

=> x = -9/2

Answer 3

3. ( 2x/5 - 2 ) : -5 = 3/7

=> 2x/5 - 2 = 3/7 . (-5)

=> 2x/5 - 2 = -15/7

=> 2x/5 = -15/7 + 2 = -1/7

=> 2x = -1/7 . 5 = -5/7

=> x = -5/7 : 2 

=> x = -5/14

Answer 4

4.

x + 20%x = -4,8

=> 6/5x = -4,8

=> x = -4,8 : 6/5

=> x = -5/12

Answer 5

5. 

x - 15%x = -2 11/20

=> 17/20x = -51/20

=> x = -51/20 : 17/20

=> x = -3

Answer 6

6. 

( x . 25% - 2/3 ) : 2 1/3 = 1 5/8

=> x . 1/4 - 2/3 = 13/8 . 7/3 

=> x . 1/4 - 2/3 = 91/24

=> x . 1/4 = 91/24 + 2/3

=> x . 1/4 = 107/24

=> x = 107/24 : 1/4

=> x = 107/6