0=-2.8t^2+45t+125

Solution for 0=-2.8t^2+45t+125 equation:

0=-2.8t^2+45t+125

We move all terms to the left:

0-(-2.8t^2+45t+125)=0

We add all the numbers together, and all the variables

-(-2.8t^2+45t+125)=0

We get rid of parentheses

2.8t^2-45t-125=0

a = 2.8; b = -45; c = -125;
Δ = b2-4ac
Δ = -452-4·2.8·(-125)
Δ = 3425
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:

$\sqrt{\Delta}=\sqrt{3425}=\sqrt{25*137}=\sqrt{25}*\sqrt{137}=5\sqrt{137}$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-45)-5\sqrt{137}}{2*2.8}=\frac{45-5\sqrt{137}}{5.6}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-45)+5\sqrt{137}}{2*2.8}=\frac{45+5\sqrt{137}}{5.6}
$