This is in Calculus and its multiple choice only. Provide necessary solutions for each items. Just follow the numbering. Write the correct answer if not in the choices. Thank you and Godbless.

29. Determine the local minimum value of the function y =(x) defined implicitly in the equation x' + 3xy + 4y = 4. 5-7 4-7 A) 7 C) 7 3-7 B) 7 D) 14 30. The curve y = x (x -2) is decreasing on the interval A) (0,1.7) C) (0,1.5) B) (0,1.6) D) (0,1.8) 31. Using differential, determine the increase in volume of a sphere when its radius changes from 20 cm to 20.1 cm. A) 500.2 cm C) 502.7 cm' B) 501.5 cm' D) 504.4 cm