8.7(t)=-4.9t^2+27.5t+8.7

Solution for 8.7(t)=-4.9t^2+27.5t+8.7 equation:

8.7(t)=-4.9t^2+27.5t+8.7

We move all terms to the left:

8.7(t)-(-4.9t^2+27.5t+8.7)=0

We get rid of parentheses

4.9t^2-27.5t+8.7t-8.7=0

We add all the numbers together, and all the variables

4.9t^2-18.8t-8.7=0

a = 4.9; b = -18.8; c = -8.7;
Δ = b2-4ac
Δ = -18.82-4·4.9·(-8.7)
Δ = 523.96
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{-(-18.8)-\sqrt{523.96}}{2*4.9}=\frac{18.8-\sqrt{523.96}}{9.8}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-18.8)+\sqrt{523.96}}{2*4.9}=\frac{18.8+\sqrt{523.96}}{9.8}
$