0=7x-1.86x^2

Solution for 0=7x-1.86x^2 equation:

0=7x-1.86x^2

We move all terms to the left:

0-(7x-1.86x^2)=0

We add all the numbers together, and all the variables

-(7x-1.86x^2)=0

We get rid of parentheses

1.86x^2-7x=0

a = 1.86; b = -7; c = 0;
Δ = b2-4ac
Δ = -72-4·1.86·0
Δ = 49
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{49}=7$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-7)-7}{2*1.86}=\frac{0}{3.72}
=0
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-7)+7}{2*1.86}=\frac{14}{3.72}
=3+2.84/3.72
$