How do I simplify an expression that's already simplified? (Example 8x + 13x)

Which two fractions are equivalent to 6/11? 6/22 and 18/33 12/22 and 18/33 12/22 and 18/22 3/5 and 6/10

If 7x=9y, y/z = 7/5 , then x/z = (a) 2/7 (b) 7/9 (c) 9/5 (d) 9/7 (e) 5/9

Suppose m: angle a =77 degrees what is the measure of a complement of a complement of angle a, what is a conclusion you can draw about a complement of a complement of an angle