Solve 5x^2=2.45

$$5 { x }^{ 2 } =2.45$$

Solve for x

$$x=0.7$$

$$x=-0.7$$

Steps Using Difference of Squares

Divide both sides by 5.

$$x^{2}=\frac{2.45}{5}$$

Expand \frac{2.45}{5} by multiplying both numerator and the denominator by 100.

$$x^{2}=\frac{245}{500}$$

Reduce the fraction \frac{245}{500} to lowest terms by extracting and canceling out 5.

$$x^{2}=\frac{49}{100}$$

Subtract \frac{49}{100} from both sides.

$$x^{2}-\frac{49}{100}=0$$

Multiply both sides by 100.

$$100x^{2}-49=0$$

Consider 100x^{2}-49. Rewrite 100x^{2}-49 as \left(10x\right)^{2}-7^{2}. The difference of squares can be factored using the rule: a^{2}-b^{2}=\left(a-b\right)\left(a+b\right).

$$\left(10x-7\right)\left(10x+7\right)=0$$

To find equation solutions, solve 10x-7=0 and 10x+7=0.

$$x=\frac{7}{10} x=-\frac{7}{10}$$

Steps by Finding Square Root

Divide both sides by 5.

$$x^{2}=\frac{2.45}{5}$$

Expand \frac{2.45}{5} by multiplying both numerator and the denominator by 100.

$$x^{2}=\frac{245}{500}$$

Reduce the fraction \frac{245}{500} to lowest terms by extracting and canceling out 5.

$$x^{2}=\frac{49}{100}$$

Take the square root of both sides of the equation.

$$x=\frac{7}{10} x=-\frac{7}{10}$$

Steps Using the Quadratic Formula

Divide both sides by 5.

$$x^{2}=\frac{2.45}{5}$$

Expand \frac{2.45}{5} by multiplying both numerator and the denominator by 100.

$$x^{2}=\frac{245}{500}$$

Reduce the fraction \frac{245}{500} to lowest terms by extracting and canceling out 5.

$$x^{2}=\frac{49}{100}$$

Subtract \frac{49}{100} from both sides.

$$x^{2}-\frac{49}{100}=0$$

This equation is in standard form: ax^{2}+bx+c=0. Substitute 1 for a, 0 for b, and -\frac{49}{100} for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.

$$x=\frac{0±\sqrt{0^{2}-4\left(-\frac{49}{100}\right)}}{2}$$

Square 0.

$$x=\frac{0±\sqrt{-4\left(-\frac{49}{100}\right)}}{2}$$

Multiply -4 times -\frac{49}{100}.

$$x=\frac{0±\sqrt{\frac{49}{25}}}{2}$$

Take the square root of \frac{49}{25}.

$$x=\frac{0±\frac{7}{5}}{2}$$

Now solve the equation x=\frac{0±\frac{7}{5}}{2} when ± is plus.

$$x=\frac{7}{10}$$

Now solve the equation x=\frac{0±\frac{7}{5}}{2} when ± is minus.

$$x=-\frac{7}{10}$$

The equation is now solved.

$$x=\frac{7}{10} x=-\frac{7}{10}$$