300=0.0089t2+1.1149t+78.4491

Solution for 300=0.0089t2+1.1149t+78.4491 equation:

300=0.0089t^2+1.1149t+78.4491

We move all terms to the left:

300-(0.0089t^2+1.1149t+78.4491)=0

We get rid of parentheses

-0.0089t^2-1.1149t-78.4491+300=0

We add all the numbers together, and all the variables

-0.0089t^2-1.1149t+221.5509=0

a = -0.0089; b = -1.1149; c = +221.5509;
Δ = b2-4ac
Δ = -1.11492-4·(-0.0089)·221.5509
Δ = 9.13021405
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{-(-1.1149)-\sqrt{9.13021405}}{2*-0.0089}=\frac{1.1149-\sqrt{9.13021405}}{-0.0178}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1.1149)+\sqrt{9.13021405}}{2*-0.0089}=\frac{1.1149+\sqrt{9.13021405}}{-0.0178}
$