Question

Tìm STN x biết.

70 - 5. (X-3) = 45

12+ (5+x) = 20

130-( 100+x) = 25

175 + (30 - x) = 200

5(x + 12) + 22 = 92

95-5(x+2) = 45

14x +54 = 82

15x -133 = 17

155-10(x + 1) = 55

Answer 1

1) 70 - 5( x - 3 ) = 45

5( x - 3 ) = 70 - 45

5( x - 3 ) = 25

x - 3 = 25 : 5

x - 3 = 5

x = 5 + 3

x = 8

2) 12 + ( 5 + x ) = 20

5 + x = 20 - 12

5 + x = 8

x = 8 - 5

x = 3

3) 130 - ( 100 + x ) = 25

100 + x = 130 - 25

100 + x = 105

x = 105 - 100

x = 5

4) 175 + ( 30 - x ) = 200

30 - x = 200 - 175

30 - x = 25

x = 30 - 25

x = 5

Answer 2

5) 5( x + 12 ) + 22 = 92

5( x + 12 ) = 92 - 22

5( x + 12 ) = 70

x + 12 = 70 : 5

x + 12 = 14

x = 14 - 12

x = 2

6) 95 - 5( x + 2 ) = 45

5( x + 2 ) = 95 - 45

5( x + 2 ) = 50

x + 2 = 50 : 5

x + 2 = 10

x = 10 - 2

x = 8

7) 14x + 54 = 82

14x = 82 - 54

14x = 28

x = 28 : 14

x = 2

8) 15x - 133 = 17

15x = 17 + 133

15x = 150

x = 150 : 15

x = 10

9) 155 - 10( x + 1 ) = 55

10( x + 1 ) = 155 - 55

10( x + 1 ) = 100

x + 1 = 100 : 10

x + 1 = 10

x = 10 - 1

x = 9