C. Y = 75x + 125
Number of credits jumps two from 3 to 5 and the yearly cost jumps from $350 to $500...
$500 - $350 = $150
$150 ÷ by 2 (number of credits) equals $75 (per number of credit)
Thus, we can do:
$75 x 5 = $375
$500 - $375 = $125
I hope that helps...! :>
