Question

Determine the point of intersection of the curve on the y-axis, obtained by plotting $x^2-2x-3=0$.

• A. (0, -3)
• B. (0, 3)
• C. (0, -1)
• D. Cannot be determined

Answer 1

The correct option is A (0, -3)

To plot the graph of $y=x^2-2x-3$, form the following table by assigning integer values from -3 to 4 for x and finding corresponding values of $y=x^2-2x-3$.
$\begin{array}{ccccccccc}x& -3& -2& -1& 0& 1& 2& 3& 4\\ x^2& 9& 4& 1& 0& 1& 4& 9& 16\\ -2x& 6& 4& 2& 0& -2& -4& -6& -8\\ -3& -3& -3& -3& -3& -3& -3& -3& -3\\ y& 12& 5& 0& -3& -4& -3& 0& 5\end{array}$
Plot the points (-3, 12), (-2, 5), (-1, 0), (0, -3), (2, -3), (3, 0), (4, 5) and join the points by a smooth curve.
It is clear from the graph that the curve intersects the y-axis at one point(at -3).