Question

Solve.

2x^2 + x – 1 = 9

How to solve this?

Answer 1

First we need to organize the equation.
\[2x^{2} + x -1 = 9 \]
\[2x^{2} + x - 1 - 9 =0 \]
\[2x^{2} + x - 10 =0 \]

Now lets us the Quadratic Formula.
\[ x = \frac{-b \pm \sqrt{b^{2} -4ac}}{2a} \]
Now all we have to do is plug our values into the fromula and solve
\[ x = \frac{-1 \pm \sqrt{1^{2} -4(2)(-10)}}{2(2)} \]

The answer will be
\[ x = -\frac{5}{2} \] and \[ x = 2\]

Answer 2

Ooh! Thanks a bunch! Do you think you could help me with my next problem?