A student solving a physics problem to find the unknown has applied physics principles and obtained the expression: μkmgcosθ=mgsinθ−ma, where g=9.80meter/second2, a=3.60meter/second2, θ=27.0∘, and m is not given. Which of the following represents a simplified expression for μk?

A student solving a physics problem to find the unknown has applied physics principles and obtained the expression: , where , , , and is not given. Which of the following represents a simplified expression for ?

a. tanθ− ag
b. To avoid making mistakes, the expression should not be simplified until the numerical values are substituted.
c. gsinθ−agcosθ
d. The single equation has two unknowns and cannot be solved with the information given.