5(x^2)+2.8(x)=1

Solution for 5(x^2)+2.8(x)=1 equation:

5(x^2)+2.8(x)=1

We move all terms to the left:

5(x^2)+2.8(x)-(1)=0

a = 5; b = 2.8; c = -1;
Δ = b2-4ac
Δ = 2.82-4·5·(-1)
Δ = 27.84
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{-(2.8)-\sqrt{27.84}}{2*5}=\frac{-2.8-\sqrt{27.84}}{10}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2.8)+\sqrt{27.84}}{2*5}=\frac{-2.8+\sqrt{27.84}}{10}
$