Question 3
Find two numbers whose sum is 27 and product is 182.
- Let one of the numbers be . Since their sum is , the other number is .
- Their product is given as , which allows us to set up a quadratic equation: .
- Solving this quadratic equation by factorisation gives the values of the two numbers.
Step 1 · Formulate the Quadratic Equation
Let the first number be . Since the sum of the two numbers is , the second number is .
Given their product is
Step 2 · Solve by Factorisation
Find two numbers whose sum is and product is . The numbers are and .
Step 3 · Find the Numbers
Setting each factor to zero:
- If , the second number is .
- If , the second number is .
and
- Sign Error in Splitting Middle Term: Selecting and gives a sum of , whereas the coefficient is . Both factors must be negative ( and ) so that their product is and sum is .
- Incomplete Answer: Stopping after finding or without calculating and stating both required numbers.
More questions in Exercise 4.2
Find the roots of the following quadratic equations by factorisation:
(i)
(ii)
(iii)
(iv)
(v)
Solve the problems given in Example 1.
Find two numbers whose sum is 27 and product is 182.
Find two consecutive positive integers, sum of whose squares is 365.
The altitude of a right triangle is 7 cm less than its base. If the hypotenuse is 13 cm, find the other two sides.
A cottage industry produces a certain number of pottery articles in a day. It was observed on a particular day that the cost of production of each article (in rupees) was 3 more than twice the number of articles produced on that day. If the total cost of production on that day was ₹ 90, find the number of articles produced and the cost of each article.