t^2-t=18

Solution for t^2-t=18 equation:

t^2-t=18

We move all terms to the left:

t^2-t-(18)=0

We add all the numbers together, and all the variables

t^2-1t-18=0

a = 1; b = -1; c = -18;
Δ = b2-4ac
Δ = -12-4·1·(-18)
Δ = 73
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)-\sqrt{73}}{2*1}=\frac{1-\sqrt{73}}{2}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1)+\sqrt{73}}{2*1}=\frac{1+\sqrt{73}}{2}
$