How do i solve this and what property do i use?

How can we find the measure of an exterior angle if we know the measurement of an interior angle

Which of the choices shown could be used to prove that aacp=abcp ?

Which equation shows the variable terms isolated on one side and the constant terms isolated on the other side for the equation -1/2x+3=4-1/4x? a. -1/4x=1 b. -3/4x=1 c. 7=1/4x d. 7=3/4x