Question

tìm x biết a,(9x + 2 ). 3 = 60
               b, 71 +( 26 - 3x ) : 5 = 75
               c, ( 2x + 1 ) .5 = 35
               d, 42 + ( 30 - 2x ) : 3 = 50

 

Answer 1

Tìm x biết

a, (9x + 2 ) . 3 = 60

(9x + 2 ) = 60 : 3

(9x + 2 ) = 20

9x = 20 - 2

9x = 18

x = 18 : 9

x = 2

b, 71 + (26 - 3x) : 5 = 75

(26 - 3x) : 5 = 75 - 71

(26 - 3x) : 5 = 4

(26 - 3x) = 4 . 5

(26 - 3x) = 20

3x = 26 - 20

3x = 6

x = 6 : 3

x = 2

c, (2x + 1) . 5 = 35

(2x + 1) = 35 : 5

(2x + 1) = 7

2x = 7 - 1

2x = 6

x = 6 : 2

x = 3

d, 42 + (30 - 2x) : 3 = 50

(30 - 2x) : 3 = 50 - 42

(30 - 2x) : 3 = 8

(30 - 2x) = 8 . 3

(30 - 2x) = 24

2x = 30 - 24

2x = 6 

x = 6 : 2

x = 3.

Answer 2

Tìm x biết

a, (9x + 2 ) . 3 = 60

(9x + 2 ) = 60 : 3

(9x + 2 ) = 20

9x = 20 - 2

9x = 18

x = 18 : 9

x = 2

b, 71 + (26 - 3x) : 5 = 75

(26 - 3x) : 5 = 75 - 71

(26 - 3x) : 5 = 4

(26 - 3x) = 4 . 5

(26 - 3x) = 20

3x = 26 - 20

3x = 6

x = 6 : 3

x = 2

c, (2x + 1) . 5 = 35

(2x + 1) = 35 : 5

(2x + 1) = 7

2x = 7 - 1

2x = 6

x = 6 : 2

x = 3

d, 42 + (30 - 2x) : 3 = 50

(30 - 2x) : 3 = 50 - 42

(30 - 2x) : 3 = 8

(30 - 2x) = 8 . 3

(30 - 2x) = 24

2x = 30 - 24

2x = 6 

x = 6 : 2

x = 3