Solve -3x^2+2x+10

$$-3 { x }^{ 2 } +2x+10$$

Factor

$$-3\left(x-\frac{1-\sqrt{31}}{3}\right)\left(x-\frac{\sqrt{31}+1}{3}\right)$$

Steps Using the Quadratic Formula

Quadratic polynomial can be factored using the transformation ax^{2}+bx+c=a\left(x-x_{1}\right)\left(x-x_{2}\right), where x_{1} and x_{2} are the solutions of the quadratic equation ax^{2}+bx+c=0.

$$-3x^{2}+2x+10=0$$

All equations of the form ax^{2}+bx+c=0 can be solved using the quadratic formula: \frac{-b±\sqrt{b^{2}-4ac}}{2a}. The quadratic formula gives two solutions, one when ± is addition and one when it is subtraction.

$$x=\frac{-2±\sqrt{2^{2}-4\left(-3\right)\times 10}}{2\left(-3\right)}$$

Square 2.

$$x=\frac{-2±\sqrt{4-4\left(-3\right)\times 10}}{2\left(-3\right)}$$

Multiply -4 times -3.

$$x=\frac{-2±\sqrt{4+12\times 10}}{2\left(-3\right)}$$

Multiply 12 times 10.

$$x=\frac{-2±\sqrt{4+120}}{2\left(-3\right)}$$

Add 4 to 120.

$$x=\frac{-2±\sqrt{124}}{2\left(-3\right)}$$

Take the square root of 124.

$$x=\frac{-2±2\sqrt{31}}{2\left(-3\right)}$$

Multiply 2 times -3.

$$x=\frac{-2±2\sqrt{31}}{-6}$$

Now solve the equation x=\frac{-2±2\sqrt{31}}{-6} when ± is plus. Add -2 to 2\sqrt{31}.

$$x=\frac{2\sqrt{31}-2}{-6}$$

Divide -2+2\sqrt{31} by -6.

$$x=\frac{1-\sqrt{31}}{3}$$

Now solve the equation x=\frac{-2±2\sqrt{31}}{-6} when ± is minus. Subtract 2\sqrt{31} from -2.

$$x=\frac{-2\sqrt{31}-2}{-6}$$

Divide -2-2\sqrt{31} by -6.

$$x=\frac{\sqrt{31}+1}{3}$$

Factor the original expression using ax^{2}+bx+c=a\left(x-x_{1}\right)\left(x-x_{2}\right). Substitute \frac{1-\sqrt{31}}{3} for x_{1} and \frac{1+\sqrt{31}}{3} for x_{2}.

$$-3x^{2}+2x+10=-3\left(x-\frac{1-\sqrt{31}}{3}\right)\left(x-\frac{\sqrt{31}+1}{3}\right)$$

Evaluate

$$10+2x-3x^{2}$$