12=4.9x^2+30x+12

Solution for 12=4.9x^2+30x+12 equation:

12=4.9x^2+30x+12

We move all terms to the left:

12-(4.9x^2+30x+12)=0

We get rid of parentheses

-4.9x^2-30x-12+12=0

We add all the numbers together, and all the variables

-4.9x^2-30x=0

a = -4.9; b = -30; c = 0;
Δ = b2-4ac
Δ = -302-4·(-4.9)·0
Δ = 900
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{900}=30$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-30)-30}{2*-4.9}=\frac{0}{-9.8}
=0
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-30)+30}{2*-4.9}=\frac{60}{-9.8}
=-6+1/8.1666666666667
$