A stone is thrown vertically upward from a platform that is 20 feet high at a rate of 160 ft/sec. Using the quadratic function h(t) = -16t^2+160t+20 to find how long will it take the stone to reach its maximum height, and then find the maximum height. How long will it take for the stone to hit the ground

1- is the product of two rational numbers irrational or rational? first, make a hypothesis by multiplying two rational numbers. then, use variables such as x=a/b and y=c/d and the closure property of integers to prove your hypothesis. 2- 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. 3- 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 part b?