Respuesta :

Step-by-step explanation:

F(x) = ∫ₐˣ t⁷ dt

F(x) is the area under f(t) between t=a and t=x.  When x=a, the width of the interval is 0, so the area is zero.

F(6) = 0, so a = 6.

F(x) = ∫₆ˣ t⁷ dt

F(6) = ∫₆⁶ t⁷ dt

F(6) = 0