0.7(2-x)=x^2+0.8

Solution for 0.7(2-x)=x^2+0.8 equation:

0.7(2-x)=x^2+0.8

We move all terms to the left:

0.7(2-x)-(x^2+0.8)=0

We add all the numbers together, and all the variables

0.7(-1x+2)-(x^2+0.8)=0

We multiply parentheses

-0.7x-(x^2+0.8)+1.4=0

We get rid of parentheses

-x^2-0.7x-0.8+1.4=0

We add all the numbers together, and all the variables

-1x^2-0.7x+0.6=0

a = -1; b = -0.7; c = +0.6;
Δ = b2-4ac
Δ = -0.72-4·(-1)·0.6
Δ = 2.89
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{-(-0.7)-\sqrt{2.89}}{2*-1}=\frac{0.7-\sqrt{2.89}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.7)+\sqrt{2.89}}{2*-1}=\frac{0.7+\sqrt{2.89}}{-2}
$