By reducing 21/30 you dived 21 and 30 by 3 and you will get 7/10. Is 7/10 larger than 2/3? If we put these fractions in decimal form we will see 7/10 turns into 0.7 and 2/3 turns into 0.667. So the answer is 21/30 is larger than 2/3.
This is a direct variation
C = pi*d
pi is a constant and it does thru (0,0)
Answer with factoring: 2(3y+4)
Answer with simplifying: 6y+8