980=-16t^2+1800

Solution for 980=-16t^2+1800 equation:

980=-16t^2+1800

We move all terms to the left:

980-(-16t^2+1800)=0

We get rid of parentheses

16t^2-1800+980=0

We add all the numbers together, and all the variables

16t^2-820=0

a = 16; b = 0; c = -820;
Δ = b2-4ac
Δ = 02-4·16·(-820)
Δ = 52480
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{52480}=\sqrt{256*205}=\sqrt{256}*\sqrt{205}=16\sqrt{205}$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-16\sqrt{205}}{2*16}=\frac{0-16\sqrt{205}}{32}
=-\frac{16\sqrt{205}}{32}
=-\frac{\sqrt{205}}{2}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+16\sqrt{205}}{2*16}=\frac{0+16\sqrt{205}}{32}
=\frac{16\sqrt{205}}{32}
=\frac{\sqrt{205}}{2}
$