The question is the image below. algebra 2

Can someone explain the elimination method to me for this problem?

Astudent received the following grades last semester. find the student's semester grade point average. an a is algebra (3 credits), a b in history ( 3 credits), a in sociology ( 3 credits) a d in english ( 3credits) and a c in seminar ( 2credits). an a is worth 4 points, a b is worth 3 points a c is worth 2 points and a d is worth 1 point.

Look at this pattern ; 1,4,9, number 10000 belongs in this pattern . what’s the place of this number?