How do you add fractions when there is variables as the denominator?

Example: 1/a + 1/b

You make the them the same

remember that x/x=1 when x=x

so

make the bottoms the same

find the least common multipule

they don't have any common factors so just multiply them

ab is the common denomenator

so multiply 1/a by b/b to get b / (ab)

multiply 1/b by a/a to get a / (ab)

now we have

b / (ab) + a / (ab) = (b+a) / (ab) or (a+b) / (ab)