Hi,

*Note: when x = 0, then y = 0

Letting k represent the constant to see if y varies directly with x:

y = k*x  

using Pt (1,(-5/2)) to solve for k

(-5/2) = k*1

(-5/2) = k

checking k against the remaining data

-5 = (-5/2)*2

-7.5 = -7 1/2 = (-15/2)= (-5/2)*3

y = (-5/2)x      is the equation for this direct variation 

Answer by stanbon(75887)   (Show Source): You can put this solution on YOUR website!
  for the data in the table tell whether y varies directly with x if it does write an equation for the direct variation 

x y

0 0

1 -2.5

2 -5

3 -7.5

-------------

(0,0) tells you the y-intercept is 0

---

Since y decreases by 2.5 for each x-increase of one

the slope is -2.5

----

Equation:

y = -2.5x

==================

The variation is direct.

All linear function have direct variation.

------------------

Cheers,

Stan H. 

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