Evaluate square root of 3x+7=7

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

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

${\sqrt{3 x + 7}}^{2} = 7^{2}$

Simplify each side of the equation.

Use $\sqrt[n]{a^{x}} = a^{\frac{x}{n}}$ to rewrite $\sqrt{3 x + 7}$ as ${(3 x + 7)}^{\frac{1}{2}}$ .

${({(3 x + 7)}^{\frac{1}{2}})}^{2} = 7^{2}$

Simplify the left side.

Simplify ${({(3 x + 7)}^{\frac{1}{2}})}^{2}$ .

Multiply the exponents in ${({(3 x + 7)}^{\frac{1}{2}})}^{2}$ .

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

${(3 x + 7)}^{\frac{1}{2} \cdot 2} = 7^{2}$

Cancel the common factor of $2$ .

Cancel the common factor.

${(3 x + 7)}^{\frac{1}{2} \cdot 2} = 7^{2}$

Rewrite the expression.

${(3 x + 7)}^{1} = 7^{2}$

Simplify.

$3 x + 7 = 7^{2}$

Simplify the right side.

Raise $7$ to the power of $2$ .

$3 x + 7 = 49$

Solve for $x$ .

Move all terms not containing $x$ to the right side of the equation.

Subtract $7$ from both sides of the equation.

$3 x = 49 - 7$

Subtract $7$ from $49$ .

$3 x = 42$

Divide each term in $3 x = 42$ by $3$ and simplify.

Divide each term in $3 x = 42$ by $3$ .

$\frac{3 x}{3} = \frac{42}{3}$

Simplify the left side.

Cancel the common factor of $3$ .

Cancel the common factor.

$\frac{3 x}{3} = \frac{42}{3}$

Divide $x$ by $1$ .

$x = \frac{42}{3}$

Simplify the right side.

Divide $42$ by $3$ .

$x = 14$