Question

Draw the graph of $y=2x^2+x-6$ and hence solve $2x^2+x–10=0$

Answer 1

Let us draw the graph of $2x^2+x–6=0$ with the help of the table.

$\begin{array}{ccccccc}x& -4& -3& -2& 0& 1& 2\\ y& 22& 9& 0& -6& -3& 4\end{array}$

Plot the point on graph sheet

Scale: x-axis 1 cm = 2 unit; y-axis 1 cm = 2 unit

Now, by solving $y=2x^2+x-6$ and $2x^2+x–10=0$

We get, y = 4

y = 4 is a straight line parallel to x- axis.

Scale: x-axis 1 cm = 2 units; y-axis 1 cm = 2 units

The point of intersection of the parabola and the straight line is (-5/2, -4) and (2,4)

The x – coordinates of the points are {-5/2, 2}

Hence, the solution set of the equation $2x^2+x–10=0$ is {-5/2, 2}