What is the domain of the function shown in the graph below?

Domain: x<=8

Step-by-step explanation:

Domain is all the x's on a graph or all the x's that can go into an equation if you're given an equation. This graph only exists from x=8 and lower (to the left). x can be 8 and anything less than 8.

In set notation it looks like this:

{x | x<=8}

OR in interval notation:

(-infinitysymbol,8]

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