0=-5t(t-80)

Solution for 0=-5t(t-80) equation:

0=-5t(t-80)

We move all terms to the left:

0-(-5t(t-80))=0

We add all the numbers together, and all the variables

-(-5t(t-80))=0


We calculate terms in parentheses: -(-5t(t-80)), so:

-5t(t-80)

We multiply parentheses

-5t^2+400t

Back to the equation:

-(-5t^2+400t)


We get rid of parentheses

5t^2-400t=0

a = 5; b = -400; c = 0;
Δ = b2-4ac
Δ = -4002-4·5·0
Δ = 160000
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{160000}=400$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-400)-400}{2*5}=\frac{0}{10}
=0
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-400)+400}{2*5}=\frac{800}{10}
=80
$