0=-3.5t^2+210t

Solution for 0=-3.5t^2+210t equation:

0=-3.5t^2+210t

We move all terms to the left:

0-(-3.5t^2+210t)=0

We add all the numbers together, and all the variables

-(-3.5t^2+210t)=0

We get rid of parentheses

3.5t^2-210t=0

a = 3.5; b = -210; c = 0;
Δ = b2-4ac
Δ = -2102-4·3.5·0
Δ = 44100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{44100}=210$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-210)-210}{2*3.5}=\frac{0}{7}
=0
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-210)+210}{2*3.5}=\frac{420}{7}
=60
$