Ok, I just want to ask if my answer is right.

1. So there is a problem question (I'm just going to make things shorter and quicker) and the question is apparentlylog4 (64) + log1/5 (9) =

My answer is this, I turned 1/5 to 0.2 (I find it easier to solve whole numbers than fractions), then I go log(64) / log(4) = 3? Is this right? (4x4x4=64)

then I go log(9) / log(0.2) = -1.365? Is this right? So I guess 3 + (-1.365) = 1.635 is the answer to this problem? I feel like I miss something... I think...

2. Here is another one6my answer is x = -1^{x}= (1/216)^3-x,

Edit: Thanks Skeeter, sorry about question number 2, I forgot to put the 3-x, anyway I got the answer, its 4.5

3. And then there is this weird question that I can't seem to figure out the steps, it says

"The growth of a plant during an eight-month period is modelled by the exponential functionf(x) = 3(1.25)Where f(x)represents the height, in centimeters, at the end of each month and x represents the time in months. Determine when the plant will reach a height of 12 cm, to the nearest tenth of a month."^{x}

How can I figure this out when its in letters? Not even my calculator can understand it? What sorcery is this?!