For angle theta with the point (-20,-21) on it’s terminating side, what is the value of cosine

Classify the following triangle check all that apply

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.

Which letters from the table represent like terms? a and b b and c a and d b and d