Whats 9 plus 10 (hint is not 19)

Aboat costs 19200 and decreases in value by 12% per year. how much will it cost in 5 years

1- what do you think the product of a nonzero rational number and an irrational number is? is it rational or irrational? make use of variables, the closure property of integers, and possibly a proof by contradiction to prove your hypothesis.2- why do we have to specify that the rational number must be nonzero when we determine what the product of a nonzero rational number and an irrational number is? if the rational number were 0, would it give us the same result we found in the first question?

Angles r and s are complementary. the measure of angle r is 31 degrees. which equation can be used to find angle s?