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Ncert Solutions for Linear equations Class 8 CBSE Part 3



In this page we have NCERT book Solutions for Class 8th Maths:Linear equations for EXERCISE 3 . Hope you like them and do not forget to like , social share and comment at the end of the page.

Question 1

Solve and check result: 3x = 2x + 18

Answer

 3x = 2x + 18

Transposing 2x to L.H.S, we obtain

3x − 2x = 18

x = 18

Let us evaluate both the LHS and RHS for validate the answer

L.H.S = 3x = 3 × 18 = 54

R.H.S = 2x + 18 = 2 × 18 + 18 = 36 + 18 = 54

L.H.S. = R.H.S.

It proves that result is correct

Question 2

 Solve and check result: 5t − 3 = 3t − 5

Answer

5t − 3 = 3t − 5

Transposing  3t to L.H.S and −3 to R.H.S, we obtain

5t − 3t = −5 − (−3)

2t = −2

Dividing both sides by 2

t = −1

Let us evaluate both the LHS and RHS for validate the answer

L.H.S = 5t − 3 = 5 × (−1) − 3 = −8

R.H.S = 3t − 5 = 3 × (−1) − 5 = − 3 − 5 = −8

L.H.S. = R.H.S.

It proves that result is correct

Question 3

Solve and check result

 5x + 9 = 5 + 3x

Answer

 5x + 9 = 5 + 3x

Transposing 3x to L.H.S and 9 to R.H.S, we obtain

5x − 3= 5 − 9

2x = −4

Dividing both sides by 2, we obtain

= −2

Let us evaluate both the LHS and RHS for validate the answer

L.H.S = 5x + 9 = 5 × (−2) + 9 = −1

R.H.S = 5 + 3x = 5 + 3 × (−2)  = −1

L.H.S. = R.H.S.

It proves that result is correct

Question 4

 Solve and check result:

4z + 3 = 6 + 2z

Answer

 4z + 3 = 6 + 2z

Transposing 2z to L.H.S and 3 to R.H.S, we obtain

4z − 2z = 6 − 3

2z = 3

Dividing both sides by 2, we obtain

z=3/2

Let us evaluate both the LHS and RHS for validate the answer

L.H.S = 4z + 3 = 4 × (3/2) + 3 = 6 + 3 = 9

R.H.S = 6 + 2z = 6 + 2 × (3/2) = 6 + 3 = 9

L.H.S. = R.H.S.

It proves that result is correct

 

Question 5

 Solve and check result:

 2x − 1 = 14 − x

Answer

 2x − 1 = 14 − x

Transposing x to L.H.S and 1 to R.H.S, we obtain

2x + x = 14 + 1

3x = 15

Dividing both sides by 3, we obtain

x = 5

Let us evaluate both the LHS and RHS for validate the answer

 

L.H.S = 2x − 1 = 2 × (5) − 1 = 10 − 1 = 9

R.H.S = 14 − x = 14 − 5 = 9

L.H.S. = R.H.S.

It proves that result is correct

 

Question 6

Solve and check result:

8x + 4 = 3(x − 1) + 7

Answer

 8x + 4 = 3(− 1) + 7

8x + 4 = 3x − 3 + 7

Transposing 3x to L.H.S and 4 to R.H.S, we obtain

8− 3x = − 3 + 7 − 4

5x = − 7 + 7

5x=0

x=0

Let us evaluate both the LHS and RHS for validate the answer

L.H.S = 8x + 4 = 8 × (0) + 4 = 4

R.H.S = 3(x − 1) + 7 = 3 (0 − 1) + 7 = − 3 + 7 = 4

L.H.S. = R.H.S.

It proves that result is correct

Question 7- 

Solve and check result: 

Answer

Multiplying both sides by 5, we obtain

5x = 4(x + 10)

5x = 4x + 40

Transposing 4x to L.H.S, we obtain

5x − 4x = 40

x = 40

Let us evaluate both the LHS and RHS for validate the answer

L.H.S = x = 40

R.H.S = = 40

L.H.S. = R.H.S.

It proves that result is correct

Question 8

Solve and check result: 

Answer

Transposing  7x/15 on LHS and 1 on RHS

Multiplying by 15 on both sides

10x-7x= 30

3x=30

Dividing by 3 on both the sides

x=10

Let us evaluate both the LHS and RHS for validate the answer

L.H.S = =23/3

R.H.S= =23/3

L.H.S. = R.H.S.

It proves that result is correct

Question 9

 Solve and check result

Answer

Transposing y to L.H.S and 5/3 to R.H.S, we obtain

3y=21/3

3y=7

Dividing both sides by 3, we obtain

y=7/3

Let us evaluate both the LHS and RHS for validate the answer

L.H.S. = R.H.S.

It proves that result is correct

Question 10

 Solve and check result:

Answer

Transposing 3m to R.H.S and 8/5 to L.H.S

8/5= 2m

Dividing both sides by 2

m=4/5

Let us evaluate both the LHS and RHS for validate the answer

L.H.S =  3m=12/5

R.H.S = 5m –(8/5)=12/5

L.H.S. = R.H.S.

It proves that result is correct

 


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