There are three boxes. One has apples, one has oranges and the other has apples and
oranges. The boxes are labeled wrong so that no
label is correct. Sue opens just one box, and
without looking in the box, takes out one piece of
fruit. She looks at the fruit and immediately labels
all the boxes correctly. Which box did she open
and how did she know?

the apple box

Step-by-step explanation:

answer: the first graph

step-by-step explanation:

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