There would be 81 in grade 5
and 68 in grade 6
because 10% of 90 is 9 so 90 - 9 =81
and 15% of 80 is 12 so 80 - 12 = 68
First you would take 312 and divide it by 13. Using that answer and put it over 1. Then times the answer that you just got by twelve. Then put that in a mixed number in its simplest form.
Answer:
so the axis of symmetry is x=4