WAEC Mathematics 2012 Objective — Question 46

Question 46 of 50 from the West African Examinations Council (WAEC) Mathematics 2012 Objective paper, with the correct answer and a full explanation.

(Using the same graph as Q45) What is the gradient of y=2x²−5x−3 at the point x=4?

• A. 11Correct
• B. 9
• C. 19
• D. -9

Explanation

dy/dx = 4x−5. At x=4: dy/dx = 16−5 = 11.

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