Solve x^2-6x+2<0

$$x ^ { 2 } - 6 x + 2 < 0$$

Solve for x

$$x\in \left(3-\sqrt{7},\sqrt{7}+3\right)$$

Steps Using the Quadratic Formula

To solve the inequality, factor the left hand side. 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.

$$x^{2}-6x+2=0$$

All equations of the form ax^{2}+bx+c=0 can be solved using the quadratic formula: \frac{-b±\sqrt{b^{2}-4ac}}{2a}. Substitute 1 for a, -6 for b, and 2 for c in the quadratic formula.

$$x=\frac{-\left(-6\right)±\sqrt{\left(-6\right)^{2}-4\times 1\times 2}}{2}$$

Do the calculations.

$$x=\frac{6±2\sqrt{7}}{2}$$

Solve the equation x=\frac{6±2\sqrt{7}}{2} when ± is plus and when ± is minus.

$$x=\sqrt{7}+3 x=3-\sqrt{7}$$

Rewrite the inequality by using the obtained solutions.

$$\left(x-\left(\sqrt{7}+3\right)\right)\left(x-\left(3-\sqrt{7}\right)\right)<0$$

For the product to be negative, x-\left(\sqrt{7}+3\right) and x-\left(3-\sqrt{7}\right) have to be of the opposite signs. Consider the case when x-\left(\sqrt{7}+3\right) is positive and x-\left(3-\sqrt{7}\right) is negative.

$$x-\left(\sqrt{7}+3\right)>0 x-\left(3-\sqrt{7}\right)<0$$

This is false for any x.

$$x\in \emptyset$$

Consider the case when x-\left(3-\sqrt{7}\right) is positive and x-\left(\sqrt{7}+3\right) is negative.

$$x-\left(3-\sqrt{7}\right)>0 x-\left(\sqrt{7}+3\right)<0$$

The solution satisfying both inequalities is x\in \left(3-\sqrt{7},\sqrt{7}+3\right).

$$x\in \left(3-\sqrt{7},\sqrt{7}+3\right)$$

The final solution is the union of the obtained solutions.

$$x\in \left(3-\sqrt{7},\sqrt{7}+3\right)$$