Question

Without graphing, is each system independent, dependent, or inconsistent? { -x-3y=0 x-y=4

Answer 1

First, determine if there is a solution to the equation by finding their intersection. If we are to rewrite the system of linear equations,
  
    -x -  3y = 0
    x - y = 4

The values of x and y from the equation are 3 and -1. The slopes of the equations, m, are also not the same as shown below,
   m = -A/B 

where A and B are the numerical coefficients of x and y, respectively. 
  m1 = -(-1/-3) = -1/3
  m2 = -(1/-4) = 1/4

Hence, the equations are independent. 

Answer 2

Since we can find a solution for this system of equations we can affirm this is an independent system with solution equal to (x,y) = (3,-1)

* If we graph a dependent system in the slope - intercept form, we can see that the graphs of each one are identical to each (beacuse we are representing the same line).

*An inconsistent system occurs when the equations have the same slope, but different values of intersection with the Y axis.