Question

Solve the equation $x^2–2x–3=0$ using quadratic formula.

• A. both of them are natural numbers
• B. both of them are integers
• C. one of the root is zero.
• D. roots are not real

Answer 1

The correct option is B

both of them are integers

Step 1:- For $x^2–2x–3=0$,

$\Rightarrow$ $a=1,b=-2,c=-3$

D = $b^2-4ac$

D = $(-2{)}^2–4(-3\left)\right(1)=4+12=16$.

Step 2:- By quadratic formula, $x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}$
$=\frac{2\pm \sqrt{16}}{2\left(1\right)}$
$=\frac{2+4}{2}=3,\frac{2-4}{2}=-1$

Hence the roots are 2, -1