Selina Solutions Concise Maths Class 7 Chapter 12 Simple Linear Equations (Including Word Problems) Exercise 12B is prepared with the aim of helping students perform well in the annual exam. The concept of solving an equation with the variable on both sides is covered under this exercise. The solutions PDF improves problem-solving and analytical skills among students. Students who aspire to score well in the annual exam can use Selina Solutions Concise Maths Class 7 Chapter 12 Simple Linear Equations (Including Word Problems) Exercise 12B, PDF from the links which are provided here.
Selina Solutions Concise Maths Class 7 Chapter 12: Simple Linear Equations (Including Word Problems) Exercise 12B Download PDF
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Access Selina Solutions Concise Maths Class 7 Chapter 12: Simple Linear Equations (Including Word Problems) Exercise 12B
Exercise 12B page: 140
Solve:
1. 8y – 4y = 20
Solution:
8y – 4y = 20
By further calculation
4y = 20
So we get
y = 20/4 = 5
2. 9b – 4b + 3b = 16
Solution:
9b – 4b + 3b = 16
By further calculation
8b = 16
So we get
b = 16/8 = 2
3. 5y + 8 = 8y – 18
Solution:
5y + 8 = 8y – 18
By further calculation
8y – 5y = 8 + 18
So we get
3y = 26
y = 26/3 = 8 2/3
4. 6 = 7 + 2p – 5
Solution:
6 = 7 + 2p – 5
By further calculation
2p = 6 – 7 + 5
So we get
2p = 4
p = 4/2 = 2
5. 8 – 7x = 13x + 8
Solution:
8 – 7x = 13x + 8
By further calculation
13x + 7x = 8 – 8
20x = 0
x = 0/20 = 0
6. 4x – 5x + 2x = 28 + 3x
Solution:
4x – 5x + 2x = 28 + 3x
By further calculation
4x – 5x + 2x – 3x = 28
So we get
– 2x = 28
x = 28/-2 = – 14
7. 9 + m = 6m + 8 – m
Solution:
9 + m = 6m + 8 – m
By further calculation
6m – m – m = 9 – 8
4m = 1
So we get
m = 1/4
8. 24 = y + 2y + 3 + 4y
Solution:
24 = y + 2y + 3 + 4y
By further calculation
24 – 3 = 7y
21 = 7y
So we get
y = 21/7 = 3
9. 19x + 13 – 12x + 3 = 23
Solution:
19x + 13 – 12x + 3 = 23
By further calculation
7x = 23 – 16
So we get
7x = 7
x = 7/7 = 1
10. 6b + 40 = – 100 – b
Solution:
6b + 40 = – 100 – b
By further calculation
7b = – 100 – 40
7b = -140
So we get
b = -140/7 = – 20
11. 6 – 5m – 1 + 3m = 0
Solution:
6 – 5m – 1 + 3m = 0
By further calculation
5 – 2m = 0
So we get
2m = 5
m = 5/2 = 2 1/2
12. 0.4x – 1.2 = 0.3x + 0.6
Solution:
0.4x – 1.2 = 0.3x + 0.6
By further calculation
0.1x = 1.8
Multiply and divide both numerator and denominator by 10
1/10x = 18/10
By cross multiplication
x = 18/10 × 10/1 = 18
13. 6 (x + 4) = 36
Solution:
6 (x + 4) = 36
By further calculation
6x + 24 = 36
So we get
6x = 36 – 24
6x = 12
x = 12/6 = 2
14. 9 (a + 5) + 2 = 11
Solution:
9 (a + 5) + 2 = 11
By further calculation
9a + 45 + 2 = 11
So we get
9a = 11 – 47
9a = – 36
a = -36/9 = – 4
15. 4 (x – 2) = 12
Solution:
4 (x – 2) = 12
By further calculation
4x – 8 = 12
So we get
4x = 20
x = 20/4 = 5
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