Right this is pretty simple all you do is sub the points to the equation given.
So first try the first point (2,-1) in y=-3x+7
==> -1=-3(2)+7
==>-1=1 this is not equal therefore not the right points
Then try (1,10)
==>10=-3(1)+7
==>10=4 this is incorrect therefore not the right points
Next try (3,-2)
==>-2=-3(3)+7
==>-2=-2 this is equal therefore this is the coordinates to the linear equation.
Finally try the last points to make sure you are correct.
==> -8=-3(-5)+7
==>-8=22 this is incorrect also.
Therefore the only coordinates that satisfies the equation is (3,-2)
        
             
        
        
        
Nope anyway marry Christmas
        
             
        
        
        
Answer:
210
Step-by-step explanation:
x = num of adults
x + 7.5x = 238
8.5x = 238
x = 28
#students = 238-x
                  = 210