x^2=1.64-1.64x

Solution for x^2=1.64-1.64x equation:

x^2=1.64-1.64x

We move all terms to the left:

x^2-(1.64-1.64x)=0

We add all the numbers together, and all the variables

x^2-(-1.64x+1.64)=0

We get rid of parentheses

x^2+1.64x-1.64=0

a = 1; b = 1.64; c = -1.64;
Δ = b2-4ac
Δ = 1.642-4·1·(-1.64)
Δ = 9.2496
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{-(1.64)-\sqrt{9.2496}}{2*1}=\frac{-1.64-\sqrt{9.2496}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1.64)+\sqrt{9.2496}}{2*1}=\frac{-1.64+\sqrt{9.2496}}{2}
$