2x - 1.8 = 2.4 this is a hard question i don't get plz answer

Which function is odd check all that apply a. y=sin x b. y=csc x c. y=cot x d. y=sec x

International calls require the use of a country code. many country codes a 3-digit numbers. country codes do not begin with a 0 or 1. there are no restrictions on the second and third digits. how many different 3-digit country codes are possible?

If 1/√5+1/√5+1=p+q√r , find the values of p, q and r