# How do you solve 4x²-12=0?

Mar 20, 2018

$x = \pm 3$

#### Explanation:

$4 {x}^{2} - 12 = 0$

$\implies 4 \left({x}^{2} - 3\right) = 0$

$\implies {x}^{2} - 3 = 0$

$\implies {x}^{2} = 3$

$\implies x = \pm 3$

$x = \pm \sqrt{3}$

#### Explanation:

Step 1:
Put all terms with $x$ on one side of the equation and all terms without $x$ on the other side of the equation.
$4 {x}^{2} - 12 = 0$
$4 {x}^{2} = 12$

Step 2:
Divide the equation (both sides) by largest common coefficient of 4.
${x}^{2} = 3$

Step 3:
Square the equation (both sides) to obtain $x$ on one side as the subject of the equation (what you want to find).
$x = \pm \sqrt{3}$
In Step 2, you divided the equation by the coefficient 4. Take note that you cannot divide an equation by what you are finding (which in this case is $x$), especially if you have a quadratic equation (an equation with ${x}^{n}$ where $n$ is any real number).
In Step 3, remember to always add the $\pm$ after square-rooting unless you are doing an equation for real-world values (where there are no negative answers).