I would say that its pair 1 and 3
Answer:
She made a mistake in Step 7.
Step-by-step explanation:
Step 1 through 6 are correct. Only from Step 6 to Step 7 the problem comes in: both sides of the equation are multiplied by x, however the x on the left side, by error, becomes 1. The correct state in Step 7 should look like this:

Answer:
125, 216, 343,
Step-by-step explanation:
Answer:

Step-by-step explanation:
The given functions are:
and 
By algebraic properties of functions;

We perform the long division of the two polynomials as shown in the attachment.
Therefore:

The last choice is correct