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प्रश्न
The roots of a quadratic equation are 5 and -2. Then, the equation is
(a)`x^2-3x+10=0` (b)`x^2-3x-10=0` (c)x^2+3x-10=0 (d)`x^2+3x+10=0`
उत्तर
(b)` x^2-3x-10=0`
It is given that the roots of the quadratic equation are 5 and . 2 Then, the equation is:
`x^2-(5-2)x+5xx(-2)=0`
⇒` x^2-3x-10=0`
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Solution:
We need one of the solutions of the quadratic equation as 5.
Then we can take another root as any number like a positive or negative number or zero. Here I am taking another root of the quadratic equation as 2.
Then we can form a word problem as below,
Smita is younger than her sister Mita by 3 years (5 – 2 = 3). If the product of their ages is (5 × 2 = 10). Then find their present ages.
Let the age of Mita be x.
Therefore age of Smita = x – 3
By the given condition,
x(x – 3) = 10
x2 – 3x – 10 = 0
