Question

What is the y-intercept of the curve obtained by plotting $y=2x^2+x-6$?

• A. -2
• B. -6
• C. 1.5
• D. Cannot be determined

Answer 1

The correct option is B -6

To plot the given equation, form a table by assigning integer values for x from -3 to 3 and find the corresponding values of $y=2x^2+x-6$.
$\begin{array}{cccccccc}x& -3& -2& -1& 0& 1& 2& 3\\ x^2& 9& 4& 1& 0& 1& 4& 9\\ 2x^2& 18& 8& 2& 0& 2& 8& 18\\ x& -3& -2& -1& 0& 1& 2& 3\\ -6& -6& -6& -6& -6& -6& -6& -6\\ y& 9& 0& -5& -6& -3& 4& 15\end{array}$
Plot the points (-3, 9), (-2, 0), (-1, -5), (0, -6), (1, -3), (2, 4) and (3, 15) on the graph.
Join the points by a smooth curve. The curve, thus obtained, is the graph of $y=2x^2+x-6$.
So, the curve intersects y-axis at -6. Hence, y-intercept is -6.