81t^2-100=-91

Solution for 81t^2-100=-91 equation:

81t^2-100=-91

We move all terms to the left:

81t^2-100-(-91)=0

We add all the numbers together, and all the variables

81t^2-9=0

a = 81; b = 0; c = -9;
Δ = b2-4ac
Δ = 02-4·81·(-9)
Δ = 2916
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2916}=54$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-54}{2*81}=\frac{-54}{162}
=-1/3
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+54}{2*81}=\frac{54}{162}
=1/3
$