Please help i’ll give brainliest please tysm :))

Ijust need to see how to do this. so you don’t have to answer all of them just a step by step explanation of one.

Which of the following is the true for f(x) = 5cos

Write an algebraic expression to match each statement a. four less than 8 times a number b. twice the difference of a number and six c. nine from a number squared