2x2-15x+8=5x

Solution for 2x2-15x+8=5x equation:

2x^2-15x+8=5x

We move all terms to the left:

2x^2-15x+8-(5x)=0

We add all the numbers together, and all the variables

2x^2-20x+8=0

a = 2; b = -20; c = +8;
Δ = b2-4ac
Δ = -202-4·2·8
Δ = 336
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:

$\sqrt{\Delta}=\sqrt{336}=\sqrt{16*21}=\sqrt{16}*\sqrt{21}=4\sqrt{21}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-20)-4\sqrt{21}}{2*2}=\frac{20-4\sqrt{21}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-20)+4\sqrt{21}}{2*2}=\frac{20+4\sqrt{21}}{4}
$