x > or equal to 0

I have found the intersection points of 4x^2 and 2x+y=6 to be at (-1.5,9) and (1,4) and the intersection points of 8x^2 and 2x+y=6 to be at (-1,4) and (.75,4.5)

I set up my integral to be from -1.5 to 1 = 35/6

I also tried setting up my integral from 0 to 1 = 4/3

But...this is wrong...can anyone help plz? thx