What is the domain of the function f(x)=1/(x-3)?

Domain means the numbers you can use (basically, all real numbers except for those that make undefined stuff, like dividing by zero or having square root of negative)

ok so
1/(x-3)
no sqare roots so
find what numbers make divion by 0
1/(x-3)
1/0=1/(x-3)
0=x-3
3=x
3 makes a division by 0
3 is not allowed

domain is all real numbers except for 0

In this problem it decreased 20%