SOLUTION: could you please help me evaluate this expression log(base 3) (12) - log(base3) (28) + log(base3) (63) I'm usually pretty good at these types of questions but my answer bing

Algebra ->  Inequalities -> SOLUTION: could you please help me evaluate this expression log(base 3) (12) - log(base3) (28) + log(base3) (63) I'm usually pretty good at these types of questions but my answer bing       Log On


   



Question 1094566: could you please help me evaluate this expression
log(base 3) (12) - log(base3) (28) + log(base3) (63)
I'm usually pretty good at these types of questions but my answer bing 4.5 was wrong

Found 3 solutions by addingup, MathTherapy, Alan3354:
Answer by addingup(3677) About Me  (Show Source):
You can put this solution on YOUR website!
You need to apply the change-of-base formula. For your calculations, you can use ln or log_10 as long as you use the same base for both numerator and denominator. I used ln, but either will give you the same result:
log_b(x) = (log_d(x))/(log_d(b)
log_3(12) = (ln(12))/(ln(3)) = 2.261
log_3(28) = (ln(28))/(ln(3)) = 3.033
log_3(63) = (ln(63))/(ln(3)) = 3.771
2.261-3.033+3.771 = 2.999 (the answer is probably 3 because of decimal rounding)

Answer by MathTherapy(10551) About Me  (Show Source):
You can put this solution on YOUR website!
could you please help me evaluate this expression
log(base 3) (12) - log(base3) (28) + log(base3) (63)
I'm usually pretty good at these types of questions but my answer bing 4.5 was wrong
log+%283%2C+12%29+-+log+%283%2C+28%29+%2B+log+%283%2C+63%29
log+%283%2C+12%29+-+%28log+%283%2C+28%29+-+log+%283%2C+63%29%29
log+%283%2C+12%29+-+log3+%2828%2F63%29
log+%283%2C+%2812%2F%2828%2F63%29%29%29 ====> log+%283%2C+12+%2A+%2863%2F28%29%29 =====> log+%283%2C+12+%2A+%289cross%2863%29%2F4cross%2828%29%29%29 =====> log+%283%2C+3cross%2812%29+%2A+%289%2Fcross%284%29%29%29 =====> highlight_green%28matrix%281%2C3%2C+log+%283%2C+27%29%2C+%22=%22%2C+highlight%283%29%29%29
As seen, you don't need a calculator to do this simplification, and you certainly don't have to apply change of base.
Some people don't even know what change of base is. Chances are, you don't either, but even if you do, you don't need to apply that here.

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
log(base 3) (12) - log(base3) (28) + log(base3) (63)
-------------
log%283%2C12%29+-+log%283%2C28%29+%2B+log%283%2C63%29
= log%283%2C12%2A63%2F28%29+=+log%283%2C27%29
= 3