3. The general solution of the differential equation -2x3y' + 2x2y = y3 is 2 2 (a) y = Inlate (b) y = 1 In lac | + c In actc (c) 32 = In xtc (d) y = 2 2 4. If y is the solution of the initial-value problem x2y' -3xy = -6x, y(1) = 1, then y (2) = (a) 6 (b) 10 (c) -6 (d) 2 5. The general solution of the equation (9x y + 2xy3 + 1) + (3x3 + 3x2y2 - 2)y' = 0 is (a) 9x2 + 6xy? = c (b) 3xy+xy3+x =c (c) 3x y+xy3 - 2y =c (d) 3x y + x2y3 + x - 2y = c 6. An integrating factor which makes the equation -3x2 +ey + (x3 - 2yes)y' = 0 exact is (a) I(x) = e- (b) I(x) = re- (c) I(y) = e-y (d) I(y) = ye-y