Solve by Factoring 3x = square root of 4+5x

$3 x = \sqrt{4 + 5 x}$

Step 1

Subtract $\sqrt{4 + 5 x}$ from both sides of the equation.

$3 x - \sqrt{4 + 5 x} = 0$

Step 2

Subtract $3 x$ from both sides of the equation.

$- \sqrt{4 + 5 x} = - 3 x$

Step 3

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

${(- \sqrt{4 + 5 x})}^{2} = {(- 3 x)}^{2}$

Step 4

Simplify each side of the equation.

Use $\sqrt[n]{a^{x}} = a^{\frac{x}{n}}$ to rewrite $\sqrt{4 + 5 x}$ as ${(4 + 5 x)}^{\frac{1}{2}}$ .

${(- {(4 + 5 x)}^{\frac{1}{2}})}^{2} = {(- 3 x)}^{2}$

Simplify the left side.

Simplify ${(- {(4 + 5 x)}^{\frac{1}{2}})}^{2}$ .

Apply the product rule to $- {(4 + 5 x)}^{\frac{1}{2}}$ .

${(- 1)}^{2} {({(4 + 5 x)}^{\frac{1}{2}})}^{2} = {(- 3 x)}^{2}$

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

$1 {({(4 + 5 x)}^{\frac{1}{2}})}^{2} = {(- 3 x)}^{2}$

Multiply ${({(4 + 5 x)}^{\frac{1}{2}})}^{2}$ by $1$ .

${({(4 + 5 x)}^{\frac{1}{2}})}^{2} = {(- 3 x)}^{2}$

Multiply the exponents in ${({(4 + 5 x)}^{\frac{1}{2}})}^{2}$ .

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

${(4 + 5 x)}^{\frac{1}{2} \cdot 2} = {(- 3 x)}^{2}$

Cancel the common factor of $2$ .

Cancel the common factor.

${(4 + 5 x)}^{\frac{1}{2} \cdot 2} = {(- 3 x)}^{2}$

Rewrite the expression.

${(4 + 5 x)}^{1} = {(- 3 x)}^{2}$

Simplify.

$4 + 5 x = {(- 3 x)}^{2}$

Simplify the right side.

Simplify ${(- 3 x)}^{2}$ .

Apply the product rule to $- 3 x$ .

$4 + 5 x = {(- 3)}^{2} x^{2}$

Raise $- 3$ to the power of $2$ .

$4 + 5 x = 9 x^{2}$

Step 5

Solve for $x$ .

Subtract $9 x^{2}$ from both sides of the equation.

$4 + 5 x - 9 x^{2} = 0$

Factor the left side of the equation.

Factor $- 1$ out of $4 + 5 x - 9 x^{2}$ .

Reorder the expression.

Move $4$ .

$5 x - 9 x^{2} + 4 = 0$

Reorder $5 x$ and $- 9 x^{2}$ .

$- 9 x^{2} + 5 x + 4 = 0$

Factor $- 1$ out of $- 9 x^{2}$ .

$- (9 x^{2}) + 5 x + 4 = 0$

Factor $- 1$ out of $5 x$ .

$- (9 x^{2}) - (- 5 x) + 4 = 0$

Rewrite $4$ as $- 1 (- 4)$ .

$- (9 x^{2}) - (- 5 x) - 1 \cdot - 4 = 0$

Factor $- 1$ out of $- (9 x^{2}) - (- 5 x)$ .

$- (9 x^{2} - 5 x) - 1 \cdot - 4 = 0$

Factor $- 1$ out of $- (9 x^{2} - 5 x) - 1 (- 4)$ .

$- (9 x^{2} - 5 x - 4) = 0$

Factor.

Factor by grouping.

For a polynomial of the form $a x^{2} + b x + c$ , rewrite the middle term as a sum of two terms whose product is $a \cdot c = 9 \cdot - 4 = - 36$ and whose sum is $b = - 5$ .

Factor $- 5$ out of $- 5 x$ .

$- (9 x^{2} - 5 x - 4) = 0$

Rewrite $- 5$ as $4$ plus $- 9$

$- (9 x^{2} + (4 - 9) x - 4) = 0$

Apply the distributive property.

$- (9 x^{2} + 4 x - 9 x - 4) = 0$

Factor out the greatest common factor from each group.

Group the first two terms and the last two terms.

$- ((9 x^{2} + 4 x) - 9 x - 4) = 0$

Factor out the greatest common factor (GCF) from each group.

$- (x (9 x + 4) - (9 x + 4)) = 0$

Factor the polynomial by factoring out the greatest common factor, $9 x + 4$ .

$- ((9 x + 4) (x - 1)) = 0$

Remove unnecessary parentheses.

$- (9 x + 4) (x - 1) = 0$

If any individual factor on the left side of the equation is equal to $0$ , the entire expression will be equal to $0$ .

$9 x + 4 = 0$

$x - 1 = 0$

Set $9 x + 4$ equal to $0$ and solve for $x$ .

Set $9 x + 4$ equal to $0$ .

$9 x + 4 = 0$

Solve $9 x + 4 = 0$ for $x$ .

Subtract $4$ from both sides of the equation.

$9 x = - 4$

Divide each term in $9 x = - 4$ by $9$ and simplify.

Divide each term in $9 x = - 4$ by $9$ .

$\frac{9 x}{9} = \frac{- 4}{9}$

Simplify the left side.

Cancel the common factor of $9$ .

Cancel the common factor.

$\frac{9 x}{9} = \frac{- 4}{9}$

Divide $x$ by $1$ .

$x = \frac{- 4}{9}$

Simplify the right side.

Move the negative in front of the fraction.

$x = - \frac{4}{9}$

Set $x - 1$ equal to $0$ and solve for $x$ .

Set $x - 1$ equal to $0$ .

$x - 1 = 0$

Add $1$ to both sides of the equation.

$x = 1$

The final solution is all the values that make $- (9 x + 4) (x - 1) = 0$ true.

$x = - \frac{4}{9}, 1$

Step 6

Exclude the solutions that do not make $3 x - \sqrt{4 + 5 x} = 0$ true.

$x = 1$

Solve by Factoring 3x = square root of 4+5x

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