NCERT Solutions
Class 10 - Mathematics - Chapter 4: QUADRATIC EQUATIONSExercise 4.2
Class 10 - Mathematics - Chapter 4: QUADRATIC EQUATIONS
Question. 1
Find the roots of the following quadratic equations by factorisation:
(i) \(x^2 - 3x - 10 = 0\)
(ii) \(2x^2 + x - 6 = 0\)
(iii) \(\sqrt{2}x^2 + 7x + 5\sqrt{2} = 0\)
(iv) \(2x^2 - x + \dfrac{1}{8} = 0\)
(v) \(100x^2 - 20x + 1 = 0\)
Answer:
(i) \(-2, 5\)
(ii) \(-2, \dfrac{3}{2}\)
(iii) \(-\dfrac{5}{\sqrt{2}}, -\sqrt{2}\)
(iv) \(\dfrac{1}{4}, \dfrac{1}{4}\)
(v) \(\dfrac{1}{10}, \dfrac{1}{10}\)
Question. 2
Solve the problems given in Example 1.
Example 1: Represent the following situations mathematically and solve them:
(i) John and Jivanti together have 45 marbles. Both of them lost 5 marbles each, and the product of the number of marbles they now have is 124. How many marbles did each of them have originally?
(ii) A cottage industry produces a certain number of toys in a day. The cost of production of each toy (in rupees) was found to be 55 minus the number of toys produced in a day. On a particular day, the total cost of production was ₹750. How many toys were produced on that day?
Answer:
(i) \(9, 36\)
(ii) \(25, 30\)
Question. 3
Find two numbers whose sum is 27 and product is 182.
Answer:
Numbers are 13 and 14.
Question. 4
Find two consecutive positive integers, the sum of whose squares is 365.
Answer:
Positive integers are 13 and 14.
Question. 5
The altitude of a right triangle is 7 cm less than its base. If the hypotenuse is 13 cm, find the other two sides.
Answer:
5 cm and 12 cm
Question. 6
A cottage industry produces a certain number of pottery articles in a day. The cost of production of each article is 3 rupees more than twice the number of articles produced that day. If the total cost of production is ₹90, find the number of articles produced and the cost of each article.
Answer:
Number of articles = 6, Cost of each article = ₹15