Answer:
[tex]\frac{3}{4}x=21[/tex]
Step-by-step explanation:
21 students like pizza which is the same as 3/4 of the class like pizza. The total amount of students in the class is x so 3/4 of x (or the class like pizza).
Therefore you get this equation:
[tex]\frac{3}{4}x=21[/tex]
Next, you divide 21 by 3/4, and 3/4x divided by 3/4 so you get..
[tex]\frac{3}{4}x/\frac{3}{4} =21/\frac{3}{4}[/tex]
x=21*(4/3)=28
