Brooke found the equation of the line passing through the points (–7, 25) and (–4, 13) in slope-intercept form as follows. Step 1: m = Start Fraction 13 minus 25 Over negative 4 minus (negative 7) End Fraction = Start Fraction negative 12 Over 3 End Fraction = negative 4. Step 2: y = negative 4 x + b. 25 = negative 4 (negative 7) + b. 25 = 28 + b. 25 minus 28 = 28 + b minus 28. b = negative 3. Step 3: y = negative 3 x minus 4 What was Brooke’s error? She found the incorrect slope in step 1. She mixed up the x- and y-coordinates when she plugged in the point in step 2. She found the incorrect y-intercept in step 2. She mixed up the slope and y-intercept when she wrote the equation in step 3.