Solving Quadratic Equations with Square Roots

Start by isolating $3x^2$ alone on one side by subtracting $9$ from both sides. We can then isolate the $x^2$-term by dividing both sides by $3.$ As the last step, we will square root both sides in order to solve for $x.$

$x=0$ solves the equation. Note that $x=\text{-}0$ and $x=+0$ are equal, and so there is only one solution: $x=0.$

On the left side, we have two identical terms, i.e. $x^2.$ This means the sum can be written as the product $2x^2.$ By dividing both sides by $2,$ you get $x^2$ alone on one side, and can then square root both sides.

Both $x=\text{-}10$ and $x=10$ are solutions to the equation.

Start by isolating $x^2$ on one side. Then take the square root of both sides.

Both $x=\text{-}8$ and $x=8$ are solutions to the equation.