Identify the property of real numbers that justify the work done to simplify the expression below.

Which of the following pair(s) of circles have las a common external tangent? select all that apply. a and b a and c b and c

If tan2a=cot(a+60), find the value of a, where 2a is an acute angle

60 musicians applied for a job at a music school. 14 of the musicians play both guitar and drums. what is the probability that the applicant who gets the job plays drums or guitar?