Answer:
As x coordinate of function is : -6, -4, -2, 0
And y coordinate of function is : -13, -9, -5,-1
If a function is linear it means
Slope will be same everywhere.
Slope between two points[tex](x_{1},y_{1}) \text{and} (x_{2}, y_{2})[/tex] is = [tex]\frac{y_{2}-y_{1}}{x_{2} -x_{1}}[/tex]
= [tex]\frac{-9+13}{-4+6}=\frac{4}{2}=2\\\frac{-5+9}{-2+4}=\frac{4}{2}=2\\\\\frac{-1+5}{0+2}=\frac{4}{2}=2\\\\\frac{-1+13}{0+6}=\frac{12}{6}=2[/tex]
So, between any two points slope are same i.e equal to 2.So it is a linear function.
So, Mark is right that the function is linear.
