basically, domain is all real numbers that cause an not allowed some things that aren't allowed are dividing by zero and taking the
square root of a number less than zero, restrict all values that make
thos things hapen
exapmle
a/b, b can not be zero
(3+x)/(4-x) x cannot be 4 since that would be dividing by zero
another example √(x-3) x cannot be less than 3 because that would make a sqrt of a negative
basiccally restrictions are not allowed becasue we don't understnad what happens when we break them
