27.6=-4.9t^2+27t

Solution for 27.6=-4.9t^2+27t equation:

27.6=-4.9t^2+27t

We move all terms to the left:

27.6-(-4.9t^2+27t)=0

We get rid of parentheses

4.9t^2-27t+27.6=0

a = 4.9; b = -27; c = +27.6;
Δ = b2-4ac
Δ = -272-4·4.9·27.6
Δ = 188.04
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-27)-\sqrt{188.04}}{2*4.9}=\frac{27-\sqrt{188.04}}{9.8}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-27)+\sqrt{188.04}}{2*4.9}=\frac{27+\sqrt{188.04}}{9.8}
$