Answer:
b - 28
Step-by-step explanation:
If she gives away 28 buttons that means she subtracts 28 from the amount she had
b - 28 is what she has left
Answer:
The question is incomplete, the complete question is "Changing Bases to Evaluate Logarithms in Exercise, use the change-of-base formula and a calculator to evaluate the logarithm. See Example 9.
.

Step-by-step explanation:
From the general properties or laws of logarithm, we have the

where both log are now express in the natural logarithm base.
i.e 
hence we can express our
.
the value of ln7 is 1.9459 and ln4 is 1.3863
Hence
.

B would be the correct answer. If you take 4:13 in order to form a ratio equal to that you have to multiply both sides of the ratio by the same number. 4*4=16 and 13*4=52