Need help pleaseee:3

Brady has a 20 year fixed rate mortgage for $215,500 with monthly payments of 1,305.89.the annual interest rate is 4%. what is the total cost of the principal and interest for this loan rounded to the nearest dollar

Let f(x) = x+3 and g(x) = 1/x the graph of (fog)(x) is shown below what is the range of (fog)(x)?

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?