AB Complementary

SinA = 4/5 find Cos b

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

Can someone me with the property questions for 12 13 and 14 plz