x+x-5x(5+15-2/3)=5+5-3

Solution for x+x-5x(5+15-2/3)=5+5-3 equation:

x+x-5x(5+15-2/3)=5+5-3

We move all terms to the left:

x+x-5x(5+15-2/3)-(5+5-3)=0

We add all the numbers together, and all the variables

x+x-5x(-2/3+20)-7=0

We add all the numbers together, and all the variables

2x-5x(-2/3+20)-7=0

We multiply parentheses

10x^2+2x-100x-7=0

We add all the numbers together, and all the variables

10x^2-98x-7=0

a = 10; b = -98; c = -7;
Δ = b2-4ac
Δ = -982-4·10·(-7)
Δ = 9884
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:

$\sqrt{\Delta}=\sqrt{9884}=\sqrt{4*2471}=\sqrt{4}*\sqrt{2471}=2\sqrt{2471}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-98)-2\sqrt{2471}}{2*10}=\frac{98-2\sqrt{2471}}{20}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-98)+2\sqrt{2471}}{2*10}=\frac{98+2\sqrt{2471}}{20}
$