Question

If the product of the roots of $x^2–3x+k=10$ is –2, then find the value of k.

• A. -2
• B. 8
• C. 12
• D. 6

Answer 1

The correct option is

B

8

Given quadratic equation is $x^2–3x+k=10$
$\Rightarrow x^2–3x+k-10=0$

For the equation $a{x}^2+bx+c=0$ product of the roots is $\frac{c}{a}$

Here, a = 1, b = -3 and c = k-10

Given, product of the roots of $x^2–3x+k=10$ is –2

$\Rightarrow$$\frac{k-10}{1}=-2$

$\Rightarrow k-10=-2$

$\Rightarrow k=8$