0=45t-5t^2+25

Solution for 0=45t-5t^2+25 equation:

0=45t-5t^2+25

We move all terms to the left:

0-(45t-5t^2+25)=0

We add all the numbers together, and all the variables

-(45t-5t^2+25)=0

We get rid of parentheses

5t^2-45t-25=0

a = 5; b = -45; c = -25;
Δ = b2-4ac
Δ = -452-4·5·(-25)
Δ = 2525
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:

$\sqrt{\Delta}=\sqrt{2525}=\sqrt{25*101}=\sqrt{25}*\sqrt{101}=5\sqrt{101}$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-45)-5\sqrt{101}}{2*5}=\frac{45-5\sqrt{101}}{10}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-45)+5\sqrt{101}}{2*5}=\frac{45+5\sqrt{101}}{10}
$