Question

The quadratic Formula uses the $a, b$, and $c$ from $a x^2+b x+c$, where $a, b$, and $c$ are just numbers; they are the "numerical coefficients" of the quadratic equation they've given you to solve. Now, solve the following quadratic polynomials and find out the value of $k$.
If the sum of zeroes of the quadratic polynomials $4 x^2+k x+9$ is -2 , find the value of $k$.

• A. 6
• B. 7
• C. 8
• D. 9

Answer 1

Answer: (C)

Given: $4 x^2+k x+9$
Here, $a=4, b=k, c=9$
Sum of zeroes, $(\alpha+\beta)=\frac{-b}{a}=-2$
$\Rightarrow \frac{-b}{a}=-2 $
$\Rightarrow \frac{-k}{4}=-2 \Rightarrow k=8$