In what order must she put the machines to get a final output of 5?
Substitute 6 for x in the first function.
y = 1
Let the output from the first equation become the input, x, in the second equation.
y = 1² − 6
y = −5
Incorrect. Try the other order.
Substitute 6 for x in the 2nd equation.
y = 62 − 6
y = 30
Let the output from the second equation become the input, x, in the fist equation.
y = 5
Is it possible for her to find an initial input that will get a final output of
? If so, show how she could do that. If not, explain why not.
Which equation cannot have a negative output? What input would you need from the other equation to get −5 as an output? See part (a) for more help.