Solve for a -10=- square root of a

$- 10 = - \sqrt{a}$

Rewrite the equation as $- \sqrt{a} = - 10$ .

$- \sqrt{a} = - 10$

To remove the radical on the left side of the equation, square both sides of the equation.

${(- \sqrt{a})}^{2} = {(- 10)}^{2}$

Simplify each side of the equation.

Use $\sqrt[n]{a^{x}} = a^{\frac{x}{n}}$ to rewrite $\sqrt{a}$ as $a^{\frac{1}{2}}$ .

${(- a^{\frac{1}{2}})}^{2} = {(- 10)}^{2}$

Simplify the left side.

Simplify ${(- a^{\frac{1}{2}})}^{2}$ .

Apply the product rule to $- a^{\frac{1}{2}}$ .

${(- 1)}^{2} {(a^{\frac{1}{2}})}^{2} = {(- 10)}^{2}$

Raise $- 1$ to the power of $2$ .

$1 {(a^{\frac{1}{2}})}^{2} = {(- 10)}^{2}$

Multiply ${(a^{\frac{1}{2}})}^{2}$ by $1$ .

${(a^{\frac{1}{2}})}^{2} = {(- 10)}^{2}$

Multiply the exponents in ${(a^{\frac{1}{2}})}^{2}$ .

Apply the power rule and multiply exponents, ${(a^{m})}^{n} = a^{m n}$ .

$a^{\frac{1}{2} \cdot 2} = {(- 10)}^{2}$

Cancel the common factor of $2$ .

Cancel the common factor.

$a^{\frac{1}{2} \cdot 2} = {(- 10)}^{2}$

Rewrite the expression.

$a^{1} = {(- 10)}^{2}$

Simplify.

$a = {(- 10)}^{2}$

Simplify the right side.

Raise $- 10$ to the power of $2$ .

$a = 100$