Which statements must be true? Select each correct answer. AB¯¯¯¯¯∥XZ¯¯¯¯¯ CB¯¯¯¯¯∥XY¯¯¯¯¯¯ CB=BA XY=2CA CA=12YZ

Find the value of the cosine for angle a

Iwant to know what 3g+5h+4g-2h is my teacher is too selfish to tell us

Offering 30 if a plus b plus c equals 68 and ab plus bc plus ca equals 1121, where a, b, and c are all prime numbers, find the value of abc. the answer is 1978 but i need an explanation on how to get that.