Therefore, we have y = 5x2 + 7x + 7 x = 5x3/2 + 7x1/2 + 7x−1/2. now, since the function is a sum of power functions, we can use the power rule to find its derivative. recall that according to the power rule, the derivative of xn, where n is any real number, is nxn − 1. to use the power rule, we'll have to calculate the following. 3 2 − 1 = .5 correct: your answer is correct. 1 2 − 1 = -.5 correct: your answer is correct. − 1 2 − 1 = -1.5 correct: your answer is correct. applying the power rule we have y' = 3.5 incorrect: your answer is incorrect. x1/2 + -3.5 incorrect: your answer is incorrect. x−1/2 + -1/2 incorrect: your answer is incorrect. x−3/2.