MATHdirect variation
posted by chelsea on .
Which of the following represents a direct variation function?
The answer coices are
A)d=2r
B)y=9x+1
C)y=3
D)a=1/2h(b1+b2)

A direct variation should
1. be a linear function of one variable
2. passes through the origin (0,0), i.e. if the independent variable is set to zero, the dependent variable should also be zero.
If you examine the four choices according to the above criteria, you will be able to eliminate all but the required function. 
4 + 7x + 4 = 3y