a=5

3a²= 3*5²=3*25=75

(3a)²=(3*5)²=15²=225

3a³=3*5³=3*125=375

a=-5

3a²=  75

(3a)²=225

3a³=-375

a=0.2

3a²= 0.12

(3a)²=0.36

3a³=0.024

a=-0.2

3a²= 0.12

(3a)²=0.36

3a³=-0.024

a=1/3

3a²= 3*1/9 = 1/3

(3a)²=(3*1/3)²=1

3a³=3*1/27=1/9

a=-1/3

3a²= 1/3

(3a)²=1

3a³=-1/9

a=0

3a²= 0

(3a)²=0

3a³=0

a=1/6

3a²=1/12

(3a)²=1/4

3a³=1/72