Sisters Courtney and Nina have started an internet business.

\(\text{Linear growth is a straight line with a single slope}\\ \text{It has the form }L(t) = m t + L_0 \text{ here we have}\\ L_0=2000\\ L(4)=10125 = 4m + 2000\\ m = \dfrac{8125}{4}\\ L(t) = \dfrac{8125}{4}t+2000,~t \text{ in months}\)

I'll let you fill out the table

To answer their question take a look at the difference in earnings between adjacent months.

Feb  =  8125(1)/4 + 2000 = $4031.25

Mar = 8125(2)/4 + 2000 =  $6062.50

Apr = 8125(3)/4 + 2000 = $8093.75