(x+2.3)(x)-17.6=0

Solution for (x+2.3)(x)-17.6=0 equation:

(x+2.3)(x)-17.6=0

We multiply parentheses

x^2+2.3x-17.6=0

a = 1; b = 2.3; c = -17.6;
Δ = b2-4ac
Δ = 2.32-4·1·(-17.6)
Δ = 75.69
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{-(2.3)-\sqrt{75.69}}{2*1}=\frac{-2.3-\sqrt{75.69}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2.3)+\sqrt{75.69}}{2*1}=\frac{-2.3+\sqrt{75.69}}{2}
$