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. The following shows her work. 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?
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
.She made a mistake in Step 2 when she divided by , , She should have divided , 28, by , negative 1, to get the equation , y is equal to 4 x minus 28 textsf comma, which has a slope of , , , ,
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.
She made a mistake in Step 3 when she interpreted the result. The slope of , negative 4, means that the slope of a standard-form equation is , , , ,
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.
She made a mistake in Step 1 when she added , 4 x, to both sides. She should have instead added , y, to both sides to isolate , x, and get , , , ,
She did not make a mistake.