Solve (x*2)*x=7

$$(x \times 2) \times x=7$$

Solve for x

$$x = \frac{\sqrt{14}}{2} \approx 1.870828693$$

$$x = -\frac{\sqrt{14}}{2} \approx -1.870828693$$

Steps by Finding Square Root

Multiply x and x to get x^{2}.

$$x^{2}\times 2=7$$

Divide both sides by 2.

$$x^{2}=\frac{7}{2}$$

Take the square root of both sides of the equation.

$$x=\frac{\sqrt{14}}{2} x=-\frac{\sqrt{14}}{2}$$

Steps Using the Quadratic Formula

Multiply x and x to get x^{2}.

$$x^{2}\times 2=7$$

Subtract 7 from both sides.

$$x^{2}\times 2-7=0$$

Quadratic equations like this one, with an x^{2} term but no x term, can still be solved using the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}, once they are put in standard form: ax^{2}+bx+c=0.

$$2x^{2}-7=0$$

This equation is in standard form: ax^{2}+bx+c=0. Substitute 2 for a, 0 for b, and -7 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.

$$x=\frac{0±\sqrt{0^{2}-4\times 2\left(-7\right)}}{2\times 2}$$

Square 0.

$$x=\frac{0±\sqrt{-4\times 2\left(-7\right)}}{2\times 2}$$

Multiply -4 times 2.

$$x=\frac{0±\sqrt{-8\left(-7\right)}}{2\times 2}$$

Multiply -8 times -7.

$$x=\frac{0±\sqrt{56}}{2\times 2}$$

Take the square root of 56.

$$x=\frac{0±2\sqrt{14}}{2\times 2}$$

Multiply 2 times 2.

$$x=\frac{0±2\sqrt{14}}{4}$$

Now solve the equation x=\frac{0±2\sqrt{14}}{4} when ± is plus.

$$x=\frac{\sqrt{14}}{2}$$

Now solve the equation x=\frac{0±2\sqrt{14}}{4} when ± is minus.

$$x=-\frac{\sqrt{14}}{2}$$

The equation is now solved.

$$x=\frac{\sqrt{14}}{2} x=-\frac{\sqrt{14}}{2}$$