7.

x intercepts : -1 and 1

y intercept 0

8. a) ln(3)+2.ln y - 2 ln(x-6)

b) 2 -log_{a}(b) - log_{a}(c) - 4log_{a}(d)

9. The function should pass through (1,6) and (0,2). Therefore, for a and C we have

2=C.a^{0}

6=C.a^{1
Then C=2 and a=3
10) a) X=4
}b) x should verify : e^{x}=3 or e^{x}=-2. Since the second equation does not have solution, the only solution is x=ln(3)

11.

12. The solution is in the book, pag A28