7. For the 1st-order ODE (3x3 + 3x2y2)dx + 2x3y dy = 0; Select the correct value for y(2). y(1) = 15 a. Zero, b. 1, c. V2, d. – V2, e. 2, f. – 1, g. Your Answer 8. Consider the equation y(cos’x + y sin x) dx + cos x(sin x cos x + 2y) dy = 0 The suitable integrating factor is: a) (1/cos²x), b) (1/cos x), c) cos x, d) sin x 9. The equation (2xy + 3y2)dx – (2xy + x2)dy = 0 is: a) Separable in variable first-order nonlinear homogenous ODE, b) homogenous first-order nonlinear ODE c) Exact first-order nonlinear homogenous ODE, d) None of a),b) and c) 10. Consider the equation & + 3) dx - dy = 0, the solution is: a) y4 = 4t4 In(c/t), b) y2 = x2 – x3, c) x + tan-(x/y) = 0