Write the step function shown in the graph.
Can someone please explain to me on how to do this

So, the closed circle is the input, the open circle is the output. If you put in two, you get three.

Step-by-step explanation:

I hope I'm right on this, I haven't done it in awhile. Sorry if this was wrong :(

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18