Start by isolating 3x2 alone on one side by subtracting 9 from both sides. We can then isolate the x2-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=-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. x2. This means the sum can be written as the product 2x2. By dividing both sides by 2, you get x2 alone on one side, and can then square root both sides.
Both x=-10 and x=10 are solutions to the equation.
Start by isolating x2 on one side. Then take the square root of both sides.
Both x=-8 and x=8 are solutions to the equation.