Answer:
x=4
Step-by-step explanation:
13x+7=8x+27
5x+7=27
5x=20
24
Divide 288 by 12
= 24
50%
Total students = 12 + 18 + 6 = 36
Seventh-graders = 18
18/36*100 = 50%
64 - 9 = 55 \sqrt{55} = 7.4161984871
7.4161984871/2 ≈3.7