9.4t^2-36t-15=0

Solution for 9.4t^2-36t-15=0 equation:

9.4t^2-36t-15=0

a = 9.4; b = -36; c = -15;
Δ = b2-4ac
Δ = -362-4·9.4·(-15)
Δ = 1860
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{1860}=\sqrt{4*465}=\sqrt{4}*\sqrt{465}=2\sqrt{465}$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-36)-2\sqrt{465}}{2*9.4}=\frac{36-2\sqrt{465}}{18.8}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-36)+2\sqrt{465}}{2*9.4}=\frac{36+2\sqrt{465}}{18.8}
$