Question

Which among the following is the correct graphical representation of $y=x^2+2x-3?$

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

Since the coefficient of $x^2$ is positive the parabola will be upward opening parabola, i.e. ; opening towards positive y-axis.
we get the roots of the quadratic equation by putting $y=0$
$\Rightarrow y=x^2+2x-3=0$
$\Rightarrow x^2+3x-x-3=0$
$\Rightarrow x(x+3)-1(x+3)=0$
$\Rightarrow (x+3)(x-1)=0$
$\Rightarrow x=1,-3$
From this we can say that parabola cuts the x-axis at $1$ and $-3$.