How to use order of operation in 20 divide by 4 multiply 5 = 1

What is an equivalent fraction for 5/6

F(x)= 1/x-4, g(x)=4x+1/x a. use composition to prove whether or not the functions are inverses of each other. b. express the domain of the compositions using interval notation.

Find three consecutive numbers such that the sum of one-fourth the first and one-fifth the second is five less than one-seventh the third