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CBSE Class 10 Math 2023 All Sets Solved Paper

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Question : 1 of 20
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If the zeroes of the quadratic polynomial x2+(a+1)x+bx^2 + (a + 1) x + b are 2 and -3, then
Solution:  
Given, the quadratic polynomial is x2+(a+1)x+b.x^2 + (a + 1)x + b.
The zeros of the polynomial are 2 and -3.
We have to find the value of a and b.
We know that if α and β are the zeroes of a polynomial ax2+bx+c,ax^2 + bx + c, then
Sum of the roots is α+β=ba\alpha + \beta = \frac{-b}{a}
Product of the roots is αβ=ca\alpha \beta = \frac{c}{a}
Here, α=2\alpha = 2 and β=3\beta = -3
Coefficient b = (a + 1)
Coefficient a = 1
Coefficient c = b
Sum of the roots = -b/a = -(a+1)/1 = -1 - a
α+β=23=1\alpha + \beta = 2-3 = -1
So, 1=1a-1 = -1 - a
1+a=1-1 + a = -1
a=1+1a = -1 + 1
a = 0
Product of the roots = c/a = b/(a+1)
= b/(0+1) = b
αβ=(2)(3)=6\alpha \beta = (2)(-3) = -6
So, b = -6
Therefore, the values of a and b are 0 and -6.
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