how do you make the 3 go down and to the right of the log, in the equation, log3(x+1)=4
Alan's method is probably best but if you want to start playing with LaTex you can open it up and type
log_3(x+1)=4
and this will be your output
log3(x+1)=4
Do you mean for display purposes here? Just use the subscript option in the Format menu.
log3(x+1) = 4