Every function is a relation because the numbers have relationships but not every relation is a function because for it to be a function there has to be one y fo every x if any x(input) has more than one y(output) it's not a function
Since there are 55 choices, we have to have 55 options, and for 44 questions, we multiply how many options there are in 1 question by 44 to get 55*44=2420
The first is a. you can rewrite it

the second is d. the only common factor between 20 and 40 that can be taken out is the 4 which becomes a 2, but inside the square roots there is still a 5 and 10, which cannot be combined
the third is c.

the fourth is d.
add 3 to both sides

then square both sides

then divide both sides by 2, x=50