-x(x+4.4)+7.8=1

Solution for -x(x+4.4)+7.8=1 equation:

-x(x+4.4)+7.8=1

We move all terms to the left:

-x(x+4.4)+7.8-(1)=0

We add all the numbers together, and all the variables

-x(x+4.4)+6.8=0

We multiply parentheses

-x^2-4.4x+6.8=0

We add all the numbers together, and all the variables

-1x^2-4.4x+6.8=0

a = -1; b = -4.4; c = +6.8;
Δ = b2-4ac
Δ = -4.42-4·(-1)·6.8
Δ = 46.56
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{-(-4.4)-\sqrt{46.56}}{2*-1}=\frac{4.4-\sqrt{46.56}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-4.4)+\sqrt{46.56}}{2*-1}=\frac{4.4+\sqrt{46.56}}{-2}
$