I really need help on rate changes!!

Answer: The third and fourth problem are linear
Step-by-step explanation:
3rd problem follows a pattern
X 6 5 4 3
Y 21 15 10 6
6x3+3=21
5x3=15
4x2+2=10
3x2=6
Problem 4 follows a pattern as well
X value goes up 1, Y value goes up 4