1.58-2.5x=x2

Solution for 1.58-2.5x=x2 equation:

1.58-2.5x=x2

We move all terms to the left:

1.58-2.5x-(x2)=0

We add all the numbers together, and all the variables

-1x^2-2.5x+1.58=0

a = -1; b = -2.5; c = +1.58;
Δ = b2-4ac
Δ = -2.52-4·(-1)·1.58
Δ = 12.57
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{-(-2.5)-\sqrt{12.57}}{2*-1}=\frac{2.5-\sqrt{12.57}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-2.5)+\sqrt{12.57}}{2*-1}=\frac{2.5+\sqrt{12.57}}{-2}
$