Step-by-step explanation:
Formula : r = d/t
T=?
Derive the formula leaving T alone.
T = d/r
[tex]t = (8x {}^{2} - 2x - 1)(4x + 1)[/tex]
Factor out 8x² - 2x -1 to see what we can cancel out.
[tex]t = (2x - 1)(4x + 1)(4x + 1)[/tex]
We can cancel 4x + 1 leaving ( 2x - 1 )
[tex]t = (2x - 1) \: hours[/tex]