Question

Find the zeroes of the following quadratic polynomial.
$x^2-2x-8$

• A. -4 and 2
• B. -4 and -2
• C. 4 and -2
• D. 4 and 2

Answer 1

The correct option is C 4 and -2

Comparing given polynomial with the general form $a{x}^2+bx+c$, we get

a = 1, b = - 2 and c = -8

We have $x^2–2x-8$ = $x^2–4x+2x–8$

= x (x-4) +2 (x-4)

= (x+2) (x-4)

Equating this to 0, we will get the zeroes of the polynomial.

(x-4)(x+2) = 0

$\Rightarrow$ x = 4 or x = -2

$\Rightarrow$ -2 and 4 are the two zeroes of the given polynomial.