Which one got infinite solutions

Hi my sisters and brothers can tell me the answer because i don’t understand the question

Complete the solution of the equation. find the value of y when x equals to 6 4x+y=20

Sam is a waiter at a local restaurant where he earns wages of $5 per hour sam figures that he also eams about $3 in tips for each person he serves sam works 6 hours on a particular day. if n represents the number of people sam serves that day, which of the following functions could sam use to figure ehis total earings for the do o a. en) = 30 o b. en) = 5n+ 18