1)Because if u add 8+4 which is 12 and u just leave the x with the 12 which is 12x which is ur answer.
2)if you multiply 4 and 2x or 4•2x which is 8x and you if u multiply 4 and 1 which is 4 and you are left with 8x+4 which is 12x.
Find the area of the squares.
4 ×4 = 16
Find the area of the wall.
20 × 10 =200
Divide 200 by 16.
200 ÷ 16 = 12.5
You need 12.5 squares.
15%=3
5%=1
5(20)=100
1(20)=20
So, there are 20 students in the class.