Is 21q-7p equivalent to (3q-p)(7)

Which must be true in order for the relationship △zyv ~ △xwv to be correct? zy ∥ wx ∠z ≅ ∠y and ∠w ≅ ∠x zv ≅ vy and wv ≅ vx ∠z ≅ ∠x and ∠w ≅ ∠y

Explain how you can show five less than a number using algebraic expression

Adc is formed by reflecting abc across line segment ac, as shown in the figure. if the length of ac is 4 units, the area of adc square units. it wont let me put the picture but its a triangular pyramid thats abcd