Question

16
3. If the zeros of the quadratic polynomial x^2+ (a + 1)x + b are 2 and -3, then (NCERT
(a) a = -7,6 = -1
(b) a = 5, b = -1
(c) a = 2, b = -6,
(d) a = 0, b = -6​

Answer 1

Given :

2 and -3 are the zero's of the quadratic Polynomial x^2+(a+1)x+6.

=> To find : a and b

༒︎ Solution ༒︎ :

᪥ p(x) = x^2+(a+1)x+b

᪥ As 2 and -3 are zero's of p(x)

☯︎ therefore p(2)=0 => (2)^2+(a+1)b=0 => 6+2a+b = 0 ------------------(1)

And

☯︎ p(-3) =0 => (-3)^2+(a+1)-3+b=0 => 6-3a+b = 0 ---------------------(2)

✈︎ Subtracting eq (1 ) from eq ( 2 )

➪ -5a=0 => a=0

➪ using a= 0, b= -6

➪ Hence, a=0 , b= -6

☯︎ Answer ☯︎ : Hence , the correct answer is Option d ✔︎