Answer:
Bonnie :
(0,12),(1,16)
Slope = (16 - 12) / (1 - 0) = 4/1 = 4
So Bonnie is adding $ 4 every week to her savings
Bobby :
y = 12x + 4
The slope here is 12.....so he is adding $ 12 every week to his savings
Therefore, the rate at which Bobbie is adding to his savings each week is (12 - 4) = $ 8 more then the rate at which Bonnie is adding to her savings account each week