Answer:
u=-1
Step-by-step explanation:
8x^2-x-8
6x^2 + 3x – 9-(- 2x^2 + 4x – 1 )
6x^2 + 3x – 9+2x^2 - 4x + 1
6x^2+2x^2+ 3x- 4x -9+1
He will need to drive 70 mph for the next hour for his average to be 50pmh.
Hope this helped :)