determine the points on the curve that corresponds to the given slope

y=(2x-1)(-4+2x^2) slope = 3

i tried simplifying the function

which got me 2x^3-x^2+8x+4

and equate the slope with the function

2x^3-x^2+8x+4=3

which got me

2x^3-x^2+8x-1

now how do i factor this equation and get the x-intercepts? i got stuck here....please here