Solve 5x*2x=490

$$5x \times 2x=490$$

Solve for x

$$x=7$$

$$x=-7$$

Steps by Finding Square Root

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

$$5x^{2}\times 2=490$$

Multiply 5 and 2 to get 10.

$$10x^{2}=490$$

Divide both sides by 10.

$$x^{2}=\frac{490}{10}$$

Divide 490 by 10 to get 49.

$$x^{2}=49$$

Take the square root of both sides of the equation.

$$x=7 x=-7$$

Steps Using the Quadratic Formula

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

$$5x^{2}\times 2=490$$

Multiply 5 and 2 to get 10.

$$10x^{2}=490$$

Subtract 490 from both sides.

$$10x^{2}-490=0$$

This equation is in standard form: ax^{2}+bx+c=0. Substitute 10 for a, 0 for b, and -490 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.

$$x=\frac{0±\sqrt{0^{2}-4\times 10\left(-490\right)}}{2\times 10}$$

Square 0.

$$x=\frac{0±\sqrt{-4\times 10\left(-490\right)}}{2\times 10}$$

Multiply -4 times 10.

$$x=\frac{0±\sqrt{-40\left(-490\right)}}{2\times 10}$$

Multiply -40 times -490.

$$x=\frac{0±\sqrt{19600}}{2\times 10}$$

Take the square root of 19600.

$$x=\frac{0±140}{2\times 10}$$

Multiply 2 times 10.

$$x=\frac{0±140}{20}$$

Now solve the equation x=\frac{0±140}{20} when ± is plus. Divide 140 by 20.

$$x=7$$

Now solve the equation x=\frac{0±140}{20} when ± is minus. Divide -140 by 20.

$$x=-7$$

The equation is now solved.

$$x=7 x=-7$$