Final answer:
The error may involve not correctly placing the given equation into slope-intercept form or plotting it incorrectly. The correct form of the equation is y = -x + 3, with a slope of -1 and a y-intercept of 3. The graph should be plotted accordingly.
Step-by-step explanation:
The question refers to a student error in graphing the equation y + 5 = -(x - 8). It appears the error could have occurred in rearranging the equation into slope-intercept form (y = mx + b) or in plotting the line.
To correct the error, first simplify the equation by distributing the negative sign on the right, yielding y + 5 = -x + 8.
Then, isolate y by subtracting 5 from both sides to get y = -x + 3. Now, the equation is in slope-intercept form with a slope (m) of -1 and a y-intercept (b) of 3.
To graph the line, start by plotting the y-intercept at (0, 3) on the y-axis. Then use the slope to find another point. Since the slope is -1 (which means 'down 1, over 1' to the right), from the y-intercept, move one unit down and one unit to the right to plot another point. Draw a straight line through both points to complete the graph.