-0.08t^2+1.6t+2=9

Solution for -0.08t^2+1.6t+2=9 equation:

-0.08t^2+1.6t+2=9

We move all terms to the left:

-0.08t^2+1.6t+2-(9)=0

We add all the numbers together, and all the variables

-0.08t^2+1.6t-7=0

a = -0.08; b = 1.6; c = -7;
Δ = b2-4ac
Δ = 1.62-4·(-0.08)·(-7)
Δ = 0.32
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{-(1.6)-\sqrt{0.32}}{2*-0.08}=\frac{-1.6-\sqrt{0.32}}{-0.16}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1.6)+\sqrt{0.32}}{2*-0.08}=\frac{-1.6+\sqrt{0.32}}{-0.16}
$