i'm seriously considering telling you to through that book away but if that's what your school uses, i guess you can't do that
books make mistakes once in a while, but usually not often enough for you to pin point two in the same section, and such blatant mistakes to top it all off
Please start a new thread for a new problem.
If no base is given log(4) can be either of two things, depending on who is teaching the class and what field you are in. It could either be
log_{10}(4)
or
log_e(4) = ln(e)
However as log_3(9) = log_3(3^2) = 2 I can think of only one way such that this is going to work:
log_b(4) + log_b(2) = 2
log_b(4*2) = 2
log_b(8) = 2
Using the change of base formula:
log_b(8) = ln(8)/ln(b) = 2
ln(b) = (1/2)ln(8)
b = e^{(1/2)ln(8)} = [e^{ln(8)}]^{1/2} = sqrt{8} = 2.82843
So we CAN say:
log_{sqrt{8}}(4) + log_{sqrt{8}}(2) = log_3(9)
but I doubt this is what the question was after.
-Dan