Write in Standard Form -3x-12=x-3x^2

$- 3 x - 12 = x - 3 x^{2}$

Move all the expressions to the left side of the equation.

Subtract $x$ from both sides of the equation.

$- 3 x - 12 - x = - 3 x^{2}$

Add $3 x^{2}$ to both sides of the equation.

$- 3 x - 12 - x + 3 x^{2} = 0$

Subtract $x$ from $- 3 x$ .

$- 4 x - 12 + 3 x^{2} = 0$

To write a polynomial in standard form, simplify and then arrange the terms in descending order.

$a x^{2} + b x + c = 0$

Move $- 12$ .

$- 4 x + 3 x^{2} - 12 = 0$

Reorder $- 4 x$ and $3 x^{2}$ .

$3 x^{2} - 4 x - 12 = 0$