X^2=4.3-2.15x

Solution for X^2=4.3-2.15x equation:

X^2=4.3-2.15X

We move all terms to the left:

X^2-(4.3-2.15X)=0

We add all the numbers together, and all the variables

X^2-(-2.15X+4.3)=0

We get rid of parentheses

X^2+2.15X-4.3=0

a = 1; b = 2.15; c = -4.3;
Δ = b2-4ac
Δ = 2.152-4·1·(-4.3)
Δ = 21.8225
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{-(2.15)-\sqrt{21.8225}}{2*1}=\frac{-2.15-\sqrt{21.8225}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2.15)+\sqrt{21.8225}}{2*1}=\frac{-2.15+\sqrt{21.8225}}{2}
$