Given f(x)=x*2+8 and g(x)= (x+4)/x, find (g*f)(-4)?

(g*f)(-4) = (x + 4)/x * x^2 + 8
....(x + 4)(x^2 + 8)
=-------------------------
............x

....(- 4 + 4)[(-4)^2 + 8]
=--------------------------------
.......... - 4

.....0(24)
= ----------
......- 4

= 0 answer//

Well,
i hope x*2 means x^2 (so the square : x^2 is the "correct" notation here)
and (g*f should be gof (the composition...)

so
f(x)=x*2+8 and g(x)= (x+4)/x

(g o f)(-4) = g( f(-4) ) = g( (-4^2 + 8) = g(24) = (24 + 4)/24 = 28/24 = 7/6

finally
(gof)(-4) = 7/6

et voilà !

Bonne Année from France !

hope it' ll help !!