2.2+x(-3.4);x=-2.5

Solution for 2.2+x(-3.4);x=-2.5 equation:

2.2+x(-3.4)x=-2.5

We move all terms to the left:

2.2+x(-3.4)x-(-2.5)=0

We add all the numbers together, and all the variables

x(-3.4)x+4.7=0

We multiply parentheses

-3.4x^2+4.7=0

a = -3.4; b = 0; c = +4.7;
Δ = b2-4ac
Δ = 02-4·(-3.4)·4.7
Δ = 63.92
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{63.92}}{2*-3.4}=\frac{0-\sqrt{63.92}}{-6.8}
=-\frac{\sqrt{}}{-6.8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+\sqrt{63.92}}{2*-3.4}=\frac{0+\sqrt{63.92}}{-6.8}
=\frac{\sqrt{}}{-6.8}
$