0=12x^2-280x-1000

Solution for 0=12x^2-280x-1000 equation:

0=12x^2-280x-1000

We move all terms to the left:

0-(12x^2-280x-1000)=0

We add all the numbers together, and all the variables

-(12x^2-280x-1000)=0

We get rid of parentheses

-12x^2+280x+1000=0

a = -12; b = 280; c = +1000;
Δ = b2-4ac
Δ = 2802-4·(-12)·1000
Δ = 126400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{126400}=\sqrt{1600*79}=\sqrt{1600}*\sqrt{79}=40\sqrt{79}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(280)-40\sqrt{79}}{2*-12}=\frac{-280-40\sqrt{79}}{-24}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(280)+40\sqrt{79}}{2*-12}=\frac{-280+40\sqrt{79}}{-24}
$