Question 11 Find dy/dx by implicit differentiation. xy + x = 2 O _ 1+y X O 1+x O _ 1+x y O 1+y Question 12 Find the derivative of the function. y = log3 5x + 9 O 5 In 3 O 5 2(In 3)(5x + 9) O 5 In 3 (5x + 9) 0 5 In3 5x + 9Question 13 Find the derivative of the function. y = 4 sec x + 4 cotax - 7 sin(6x3) + e6x O dy = 4 sec x tan x - - csc2-x - 126x2 cos(6x3) + 6 6x dx ay = 4 sec x tan x - = csc2x|+ 126x2 cos(6x3) + 605x O dy = 4 tan2 x - = cotox cscox|+ 126x2 cos(6x3) + @6x o d = 4 tan2x -_ cot ex csc x - 126x2 cos(6x3) + be box Question 14 Find the derivative of the function. y = - 8in(x + 8) 4- 2x O 8 (x + 8)(4 - 2x)2 32- 16x + 16In(x + 8) (x + 8)(4 -2x) 32- 16x + 16(x + 8) In(x + 8) (x + 8)(4 - 2x)2 ( 32 + 16x + 16(x + 8) In(x + 8) (x - 8)(4 - 2x)2Question 15 Find the derivative. f(x) = (5x - 3)(~x + 4) Of'(x) = 3.33x1/2 - 1.5x-1/2 + 20 Of'(x) = 3.33x1/2 - 3x-1/2 + 20 Of'(x) = 7.5x1/2 - 3x-1/2 + 20 Of'(x) = 7.5x1/2 - 1.5x-1/2 + 20 Question 16 Find the derivative. y = x 1x2+1 O dy VX 2 + 1 dx 2x2 + 1 O dy _ 2x2 + 1 dx NX 2 + 1 O dy VX 2 + 1 dx x2 + 1 O dy x2 + 1 dx VX 2 + 1Question 17 5 pts Find the derivative. o 74x3+18K2+10x+30 EIXJ- x2(x+6)2 Question 18 5 pts Solve the problem. Round your answer, if appropriate. Electrical systems are governed by Ohm's law, which states thatV = IR, where V = voltage, I = current, and R = resistance. If the current in an electrical system is decreasing at a rate of 5 A/s while the voltage remains constant at 22 V, at what rate is the resistance increasing (in Q/sec) when the current is 40 A? (Do not round your answer.) 4 O Q/sec O % Q/sec O % Q/sec 11 O W Q/sec Question 19 5 pts Solve the problem. The percent of concentration of a certain drug in the bloodstream x hours after the drug is administered is given by K(x) = . At what time is the x2+ 64 concentration a maximum? O 8 hr 3.2 hr O 6.4 hr O 3 hr Question 20 5 pts Use derivatives to find the largest open intervals where the function is concave upward. f ( x ) = x4 - 8x2 O None O (-00, - 2-/3 / 3) O (-00, - 2-1/3/3), (21/3 / 3 , 00) O (2~/3/3, 00)