My son and I are stuck on this one. Can anyone give some insight to this problem? Thank you.

I made is clear for you, now you may match each one

Step-by-step explanation:

f(1)= 11, f(n)= 3*f(n-1)

11*3= 33, 33*3= 99, 99*3= 297, ...11, 33, 99, 297...

⊕ middle

f(1)= -18, f(n)= f(n-1)+21

-18+21= 3, 3+21= 24, 24+21= 45, ...-18, 3, 24, 45, ...

f(1)= -18, f(n)= f(n-1) + 22

-18+22= 4, 4+22= 26, 26+22= 48, ...-18, 4, 26, 48, ...

f(1)= -18, f(n)= 2*f(n-1)

-18*2= -36, -36*2= -72, -72*2= -144, ...- 18, -36, -72, -144...

⊕ bottom

f(1)= -18, f(n)= 6*f(n-1)

-18*6= -108, -108*6= -648, -648*6= -3888, ...- 18, - 108, - 648, -3888, ...

⊕ top

f(1)= 11, f(n)= f(n-1) + 22

11+22= 33, 33+22= 55, 55+22= 77, ...11, 33, 55, 77, ...