Question

If the discriminant of 3x2+2x+a=0 is double the discriminant of x2-4x+2=0, then value of a is :

(a) +2 (b) -2 (c) 1 (d) -1

Answer 1

ATQ:- D=2D

So, b²-4ac= 2[b²-4ac]

(2)²-4(3)(a)= 2[(-4)²-4(1)(2)]

4-12a= 2[16-8]

4-12a= 2*8

-12a=4

a=-1/3

Hope this will help you

Answer 2

Answer:

Step-by-step explanation:

Given:

$3 \mathrm{x}^{2}+2 \mathrm{x}+\mathrm{a}=0$

To find:

the value of a

Step 1

The discriminant of $3 \mathrm{x}^{2}+2 \mathrm{x}+\mathrm{a}=0$ is double the discriminant of $\mathrm{x}^{2}-4 \mathrm{x}+2=0$

We know that the discriminant of a quadratic equation $a x^{2}+b x+c=0$ is given by: $b^{2}-4 a c$

Step 2

Hence,

$(2)^{2}-4 \times 3 \times a=2 \times\left((-4)^{2}-4 \times 1 \times 2\right)$

Simplifying the above equation then, we get

4 - 12a = 2 $\times$ (16 - 8)

4 - 12a = 16

12a = 4 - 1

12a = -12

a = -1

The value of a is -1.

Therefore, the correct answer is option (d) -1.

SPJ2