iu 9. Cho bốn điểm A(1;-1;5),B(0;0;1),C(0;2;1),D(0;3;1) . Mặt phẳng (P) chứa A,B và song song với đường thẳng CD có phương trình là 4x-z+1=0 B. 4x+y-z+1=0 2x+z-5=0 D. x+4z-1=0

Let A = (1, -1, 5), B = (0, 0, 1), C = (0, 2, 1), D = (0, 3, 1).The vector .The vector .The plane (P) contains A and B, and is parallel to the line CD. Therefore, the normal vector of the plane (P) is perpendicular to both and . We can find the normal vector by taking the cross product of and : The equation of the plane (P) is given by: where is a point on the plane. We can use point A(1, -1, 5): Therefore, the equation of the plane (P) is .Final Answer: The final answer is