# 10th cbse maths solution for exercise 4.2 part 1

This page 10th cbse maths solution for exercise 4.2 part 1is going to provide you solution for every problems that you find in the exercise no 4.2

## 10th CBSE maths solution for Exercise 4.2 part 1

(ii) 2 x² + x - 6 = 0

Solution:

2 x² + 4 x - 3 x - 6 = 0

2 x (x + 2) - 3 (x + 2) = 0

(2 x - 3) (x + 2) = 0

2 x - 3 = 0     x + 2 = 0

2 x = 3          x = -2

x = 3/2

Therefore the roots are 3/2 and -2.

(iii) √2 x² + 7 x + 5 √2 = 0

Solution:

√2 x² + 7 x + 5 √2 = 0

√2 x² + 5 x + 2 x + 5 √2 = 0

√2 x² + 5 x + √2 √2 x + 5 √2 = 0

x (√2 x + 5) + √2 (√2 x + 5) = 0

(√2 x + 5) (x + √2) = 0

√2 x + 5 = 0     x + √2 = 0

√2 x = -5          x = -√2

x = -5/√2

Therefore the roots are -5/√2 and -√2.

(iv) 2 x² - x + (1/8) = 0

Solution:

16 x²- 8 x + 1 = 0

16 x²- 4 x - 4 x + 1 = 0

4 x (4 x - 1) - 1 (4 x - 1) = 0

(4 x - 1) (4 x - 1) =0

4 x - 1 = 0     4 x - 1 = 0

4 x = 1

x = 1/4

Therefore the roots are 1/4 and 1/4.

(v) 100 x² - 20 x + 1 = 0

Solution:

100 x² - 20 x + 1 = 0

100 x² - 10 x - 10 x + 1 = 0

10 x (10 x - 1) - 1 (10 x - 1) = 0

(10 x - 1) (10 x - 1) = 0

10 x - 1 = 0

10 x = 1

x = 1/10

Therefore the roots are 1/10 and 1/10.

(i) John and Jivanti together have 45 marbles. Both of them lost 5 marbles each, and the product of the number of marbles they have now is 124. We would like to find out how many marbles they had to start with.

Solution:

Let 'x' be the number of marbles that john has

Let '45 - x' be the number of marbles that Jivanthi has

After losing 5 marbles

Number of marbles with John = x - 5

Number of marbles with Jivanti = 45 - x - 5

= 40 - x

The product of number of marbles = 124

(x - 5) (40 - x) = 124

40 x - x²- 200 + 5 x = 124

45 x - x²- 200 = 124

x²- 45 x + 124 + 200 = 0

x²- 45 x + 324 = 0

x²- 36 x - 9 x + 324 = 0

x (x - 36) - 9 (x - 36) = 0

(x - 9) (x - 36) = 0

x - 9 = 0            x - 36 = 0

x = 9              x = 36

So John is having 36 marbles,when Jivanti is having 9 marbles or Jivanti is having 36 marbles,when John is having 9 marbles.  10th cbse maths solution for exercise 4.2 part 1
10th cbse maths solution for exercise 4.2 part 1