1.25x(x+4)+.75(x-2)=16

Solution for 1.25x(x+4)+.75(x-2)=16 equation:

1.25x(x+4)+.75(x-2)=16

We move all terms to the left:

1.25x(x+4)+.75(x-2)-(16)=0

We multiply parentheses

x^2+4x+0.75x-1.5-16=0

We add all the numbers together, and all the variables

x^2+4.75x-17.5=0

a = 1; b = 4.75; c = -17.5;
Δ = b2-4ac
Δ = 4.752-4·1·(-17.5)
Δ = 92.5625
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{-(4.75)-\sqrt{92.5625}}{2*1}=\frac{-4.75-\sqrt{92.5625}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(4.75)+\sqrt{92.5625}}{2*1}=\frac{-4.75+\sqrt{92.5625}}{2}
$