4. If the zeroes of the quadratic
polynomial x2 + (a + 1) x + b are
2 and -3, then
O
(a) a = -7, b = -1
O (b) a = 5, b = -1
O (c) a = 2, b = -6
0 (, b
(d) a - 0, b = -6
Answers
Step-by-step explanation:
substitute x=2 in x2+(a+1)x+b=0
4+(a+1)×2+b=0
2a+b= -6
substitute x=(-3) in the equation
9+(a+1)×(-3)+b=0
3a+b= -12
solving 2a+b=-6 and (-3a)+b= -6 we get
a=0 and b= -6 so ans is option (d)
Correct Question :-
If the zeroes of the quadratic
equation x²+ (a + 1) x + b are
2 and -3, then
(a) a = -7, b = -1
(b) a = 5, b = -1
(c) a = 2, b = -6
(d) a = 0, b = - 6
Solution:-
So,Given x²+(a+1)x + b =0 roots are 2, -3
So, Hence roots are given So substuite in equation to get values of a,b
So Substuite x=2
(2)² + ( a + 1) 2 + b =0
4+2a+2+b =0
6+2a+b=0 ________eq1
So substuite x = -3
(-3)²+(a+1)-3+b =0
9-3a-3+b =0
6-3a +b =0 _______eq2
Subtracting eq 1 from 2
6 + 2a + b = 0
6 - 3a + b =0
___________
5a =0
a = 0
Sub value of a in eq 1
6+2a+b=0
6 + b =0
b = -6.
Hence your answer is option d
a = 0 b = -6