Question

(d) 4
If 2 is a root of the equation x² +bx+12=0, find the value of b.
(b) -8
(c) 8
(a)-4
​

Answer 1

Given:

x^2 + bx + 12 = 0

Since 2 is the root of the given equation, substitute x = 2, in the given equation, we get

(2)^2 + (b)*(2) + 12 = 0

4 + 2*b + 12 = 0

2*b + 8 = 0

2*b = - 8

b = -4 ——> Answer

Answer 2

Answer:

Option B.) -8 is the answer !!

Step-by-step explanation:

It is given that one root is 2 that's is (X-2) = 0

X = 2

Let's put this value into the equation :-

X²+ bx +12 = 0

(2)²+b(2)+12 = 0

2b +4+12 = 0

2b + 16 = 0

2b = -16.

b = –8

So Now we Have all roots of this equation X² + bX + 12 = 0

_____________________________

Extra :- It have only two roots because it's a quadratic equation And that's both root is -8 and 2 . Both are valid for the equation.

______________________________