Solve for x 1/1-2x + 6x/1+2x = 3

I assume you mean

1/(1-2x) + 6x/(1+2x) = 3
the common denominator is (1-2x)(1+2x), so we get (x ≠ ±1/2)

(1+2x) + 6x(1-2x) = (1-2x)(1+2x)
8x^2 - 8x = 0
8x(x-8) = 0

I expect you can take it from there, right?