x^2-1=1.89

Solution for x^2-1=1.89 equation:

x^2-1=1.89

We move all terms to the left:

x^2-1-(1.89)=0

We add all the numbers together, and all the variables

x^2-2.89=0

a = 1; b = 0; c = -2.89;
Δ = b2-4ac
Δ = 02-4·1·(-2.89)
Δ = 11.56
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-\sqrt{11.56}}{2*1}=\frac{0-\sqrt{11.56}}{2}
=-\frac{\sqrt{}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+\sqrt{11.56}}{2*1}=\frac{0+\sqrt{11.56}}{2}
=\frac{\sqrt{}}{2}
$