0.08x+0.06x(x+9)=1.24

Solution for 0.08x+0.06x(x+9)=1.24 equation:

0.08x+0.06x(x+9)=1.24

We move all terms to the left:

0.08x+0.06x(x+9)-(1.24)=0

We add all the numbers together, and all the variables

0.08x+0.06x(x+9)-1.24=0

We multiply parentheses

0x^2+0.08x+0x-1.24=0

We add all the numbers together, and all the variables

x^2+1.08x-1.24=0

a = 1; b = 1.08; c = -1.24;
Δ = b2-4ac
Δ = 1.082-4·1·(-1.24)
Δ = 6.1264
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{-(1.08)-\sqrt{6.1264}}{2*1}=\frac{-1.08-\sqrt{6.1264}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1.08)+\sqrt{6.1264}}{2*1}=\frac{-1.08+\sqrt{6.1264}}{2}
$