Skip to content
Related Articles

Related Articles

Improve Article
Save Article
Like Article

Class 8 NCERT Solutions- Chapter 14 Factorisation – Exercise 14.4

  • Last Updated : 03 Mar, 2021

Find and correct the errors in the following mathematical statements:

Question 1. 4(x – 5) = 4x – 5

Solution:

Given: 4(x – 5) = 4x – 5

Attention reader! All those who say programming isn't for kids, just haven't met the right mentors yet. Join the  Demo Class for First Step to Coding Coursespecifically designed for students of class 8 to 12. 

The students will get to learn more about the world of programming in these free classes which will definitely help them in making a wise career choice in the future.

Now we check if the given statement is correct or not



Taking L.H.S:

= 4(x – 5)

= 4x – 20

L.H.S ≠ R.H.S

So, the correct solution of 4(x – 5) = 4x – 20

Question 2. x(3x + 2) = 3x2+ 2

Solution:

Given: x(3x + 2) = 3x2+ 2

Now we check if the given statement is correct or not

Taking L.H.S:

= x(3x + 2)

= 3x2 + 2x

L.H.S ≠ R.H.S

So, the correct solution of x(3x + 2) = 3x2+ 2x

Question 3. 2x + 3y = 5xy

Solution:

Given: 2x + 3y = 5xy

Here, L.H.S ≠ R.H.S

So, the correct solution of 2x + 3y = 2x + 3y

Question 4. x + 2x + 3x = 5x 

Solution:



Given: x + 2x + 3x = 5x 

Now we check if the given statement is correct or not

Taking L.H.S:

= x + 2x + 3x

= 6x

L.H.S ≠ R.H.S

So, the correct solution of x + 2x + 3x = 6x

Question 5. 5y + 2y + y – 7y = 0 

Solution:

Given: 5y + 2y + y – 7y = 0 

Now we check if the given statement is correct or not

Taking L.H.S:

= 5y + 2y + y – 7y 

= y

L.H.S ≠ R.H.S

So, the correct solution of 5y + 2y + y – 7y = y

Question 6. 3x + 2x = 5x2

Solution:

Given: 3x + 2x = 5x2

Now we check if the given statement is correct or not

Taking L.H.S:

= 3x + 2x



= 5x

L.H.S ≠ R.H.S

So, the correct solution of 3x + 2x = 5x

Question 7. (2x)2+ 4(2x) + 7 = 2x2+ 8x + 7 

Solution:

Given: (2x)2+ 4(2x) + 7 = 2x2+ 8x + 7 

Now we check if the given statement is correct or not

Taking L.H.S:

= (2x)2+ 4(2x) + 7

= 4x2 + 8x + 7

L.H.S ≠ R.H.S

So, the correct solution of (2x)2+ 4(2x) + 7 = 4x2 + 8x + 7

Question 8. (2x)2+ 5x = 4x + 5x = 9x

Solution:

Given: (2x)2+ 5x = 4x + 5x = 9x

Here, 

4x + 5x ≠ 9x

So, we check (2x)2+ 5x = 4x + 5x or not

Taking L.H.S:

= (2x)2+ 5x

= 4x2 + 5x 

L.H.S ≠ R.H.S

So, the correct solution of (2x)2+ 5x = 4x2 + 5x 

Question 9. (3x + 2)2= 3x2+ 6x + 4 

Solution:

Given: (3x + 2)2= 3x2+ 6x + 4 

Now we check if the given statement is correct or not

Taking L.H.S:

= (3x + 2)2

= 9x2 + 6x + 4

L.H.S ≠ R.H.S

So, the correct solution of (3x + 2)2 = 9x2 + 6x + 4

Question 10. Substituting x = – 3 in

(a) x2+ 5x + 4 gives (– 3)2 + 5 (-3) + 4 = 9 + 2 + 4 = 15

Solution:



Given: x2+ 5x + 4

Now substitute the value of x = -3 in the given equation, 

= (-3)2+ 5(-3) + 4

= 9 – 15 + 4

= -2

So the correct solution of x2+ 5x + 4 = -2

(b) x2 – 5x + 4 gives (- 3)2 – 5 ( – 3) + 4 = 9 – 15 + 4 = – 2

Solution:

Given: x2 – 5x + 4

Now substitute the value of x = -3 in the given equation, 

= (-3)2 – 5(-3) + 4

= 9 + 15 + 4

= 28

So the correct solution of x2 – 5x + 4 = 28

(c) x2+ 5x gives (- 3)2+ 5 (-3) = – 9 – 15 = – 24

Solution:

Given: x2 + 5x 

Now substitute the value of x = -3 in the given equation, 

= (-3)2 + 5(-3) 

= 9 – 15 

= -6

So the correct solution of x2 + 5x = -6

Question 11. (y – 3)2 = y2 – 9 

Solution:

Given: (y – 3)2 = y2 – 9 

Now we check if the given statement is correct or not

Taking L.H.S:

= (y – 3)2

= y2 – 6y + 9

L.H.S ≠ R.H.S

So, the correct solution of (y – 3)2 = y2 – 6y + 9

Question 12. (z + 5)2 = z2 + 25

Solution:

Given: (z + 5)2 = z2+ 25

Now we check if the given statement is correct or not

Taking L.H.S:

= (z + 5)2

= z2 + 10z + 25

L.H.S ≠ R.H.S

So, the correct solution of (z + 5)2 = z2 + 10z + 25

Question 13. (2a + 3b) (a – b) = 2a2 – 3b2

Solution:

Given: (2a + 3b) (a – b) = 2a2 – 3b2

Now we check if the given statement is correct or not

Taking L.H.S:



= (2a + 3b) (a – b) 

= 2a2 – 2ab + 3ab – 3b

= 2a2 – 3b2 + ab 

L.H.S ≠ R.H.S

So, the correct solution of (2a + 3b) (a – b) = 2a2 – 3b2 + ab 

Question 14. (a + 4) (a + 2) = a2 + 8

Solution:

Given: (a + 4) (a + 2) = a2 + 8

Now we check if the given statement is correct or not

Taking L.H.S:

= (a + 4) (a + 2)

= a2 + 2a + 4a + 8 

= a2 + 6a + 8

L.H.S ≠ R.H.S

So, the correct solution of (a + 4) (a + 2) = a2 + 6a + 8

Question 15. (a – 4) (a – 2) = a2 – 8

Solution:

Given: (a – 4) (a – 2) = a2 – 8

Now we check if the given statement is correct or not

Taking L.H.S:

= (a – 4) (a – 2)

= a2 – 2a – 4a + 8 

= a2 – 6a + 8

L.H.S ≠ R.H.S

So, the correct solution of (a – 4) (a – 2) = a2 – 6a + 8

Question 16. 3x2/3x2 = 0

Solution:

Given: 3x2/3x2 = 0

Now we check if the given statement is correct or not

Taking L.H.S:

= 3x2/3x2

= 1

L.H.S ≠ R.H.S

So, the correct solution of 3x2/3x2 = 1

Question 17. (3x2 + 1)/(3x2) = 1 + 1 = 2

Solution:

Given: (3x2 + 1)/(3x2) = 1 + 1 = 2

Now we check if the given statement is correct or not

Taking L.H.S:

= (3x2 + 1)/(3x2)

= 3x2/(3x2) + 1/(3x2)

= 1 + 1/(3x2)

L.H.S ≠ R.H.S

So, the correct solution of (3x2 + 1)/(3x2) = 1 + 1/(3x2)

Question 18. (3x)/(3x + 2) = 1/2

Solution:

Given: (3x)/(3x + 2) = 1/2

Here, L.H.S ≠ R.H.S

So, the correct solution of (3x)/(3x + 2) = (3x)/(3x + 2)

Question 19. 3/(4x + 3) = 1/4x

Solution:

Given: 3/(4x + 3) = 1/4x

Here, L.H.S ≠ R.H.S

So, the correct solution of 3/(4x + 3) = 3/(4x + 3) 

Question 20. (4x + 5)/(4x) = 5

Solution:

Given: (4x + 5)/(4x) = 5



Now we check if the given statement is correct or not

Taking L.H.S:

= (4x + 5)/(4x) 

= (4x/4x) + 5/4x)

= 1 + 5/4x

L.H.S ≠ R.H.S

So, the correct solution of (4x + 5)/(4x) = 1 + 5/4x

Question 21. (7x + 5)/5 = 7x

Solution:

Given: (7x + 5)/5 = 7x

Now we check if the given statement is correct or not

Taking L.H.S:

= (7x + 5)/5

= (7x/5) + 5/5)

= 7x/5 + 1

L.H.S ≠ R.H.S

So, the correct solution of (7x + 5)/5 = 7x/5 + 1




My Personal Notes arrow_drop_up
Recommended Articles
Page :