Louetta is showing her friend that the slope of a line represented by an equation in standard form, Ax+By=C, can be found using a shortcut that involves the values of A and B. To do this, she rewrites −4x−y=28 in slope-intercept form. Her work follows:

Step 1: −y=28+4x
Step 2: y=−4x−28
Step 3: The slope is −4, which is the same as −(AB).

At which step, if any, did Louetta make a mistake?

A. She made a mistake in Step 1 when she added 4x to both sides. She should have instead added y to both sides to isolate x and get −4x=28+y.

B. She did not make a mistake

C. She made a mistake in Step 2 when she divided by −1. She should have divided 28 by −1 to get the equation y=4x−28, which has a slope of 4.

D. She made a mistake in Step 3 when she interpreted the result. The slope of −4 means that the slope of a standard-form equation is −A.