Answer:
A. When Katina has $280 in her bank account, 4 months have passed. Plug 4 months into Malorie's bank account equation:
a = 50(4) + 100
a = 200 + 100
a = $300
B. Malorie's bank account changes at a greater rate. Katina's bank account amount increases by $20 each month, whereas Malorie's bank account increases by $50.
Ex: month 5
Katina has 300, 20 more than the previous month.
Malorie has 350, 50 more than the previous month
1/8+ 1/4(2/8)+ 3/8+ 1/2(4/8)+ 5/8+ 3/4(6/8)+ 7/8= 28/8 = 3 1/2
Answer:
6x^2-3x
Step-by-step explanation:

Hope this helps!