What do you know about the factor method to solve quadratic equation? First of all, form a quadratic equation to show the above statement. Now solve it use factorisation. Provide more important question in quadratic equations chapter 4 class 10th for practice. It will help us in preparation of exams.
Represent the following situations mathematically: 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. We would like to find out how many marbles they had to start with.
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Let the number of marbles John had be x.
Then the number of marbles Jivanti had = 45 – x (Why?).
The number of marbles left with John, when he lost 5 marbles = x – 5
The number of marbles left with Jivanti, when she lost 5 marbles = 45 – x – 5
= 40 – x
Therefore, their product = (x – 5) (40 – x)
= 40x – x2 – 200 + 5x
= – x2 + 45x – 200
So, – x2 + 45x – 200 = 124 (Given that product = 124)
i.e., – x2 + 45x – 324 = 0
i.e., x2 – 45x + 324 = 0
Therefore, the number of marbles John had, satisfies the quadratic equation
x2 – 45x + 324 = 0
which is the required representation of the problem mathematically.