Question

Who can help me number 5 please?

Answer 1

You have the right answer I think!!

Answer 2

You have established that c = -2 in question 4.

From the graph, the point g(3)=0 seems usable, so let's go with that.

g(3) = a·b³ - 2 = 0, so a = 2/b³

g(2) = -1 seems also plotted, so g(2) = a·b² - 2 = -1 ⇒ a = 1/b²

Solve for b gives:

2/b³ = 1/b² ⇒ (multiply by b³) 2 = b

From this you can find a=1/4 

Note that this is only true if indeed g(3)=0 and g(2)=-1. I just assume that from the graph.