Question

hi this question is kinda creativeso the first two pictures is the marking scheme and the third picture is the student's answercan you tell me where did the student do wrong?

Answer 1

From the given picture of student 1

for x = -1

When you substitute it in dy/dx it will give you a slope = 3/4 which is wrong

The given slope is -3/4, then

You have to reject x = -1 and use only x = 5, then q has only one value

From the given picture of student 2

The numerator is -x + 2

She took (-) to cancel the (-) on the other side, then

She must take (-) as a common factor from -x and 2, then

It must be x - 2, not x +2

Then the right side should be 4x - 8, not 4x + 8