3+8.5x(x=4)

Solution for 3+8.5x(x=4) equation:

3+8.5x(x=4)

We move all terms to the left:

3+8.5x(x-(4))=0

We multiply parentheses

8x^2-32x+3=0

a = 8; b = -32; c = +3;
Δ = b2-4ac
Δ = -322-4·8·3
Δ = 928
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{928}=\sqrt{16*58}=\sqrt{16}*\sqrt{58}=4\sqrt{58}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-32)-4\sqrt{58}}{2*8}=\frac{32-4\sqrt{58}}{16}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-32)+4\sqrt{58}}{2*8}=\frac{32+4\sqrt{58}}{16}
$