Please show your work. It would help me understand this problem a lot better. Thank you!

(1 point) Find an orthonormal basis of the plane x1 + 2x2 X3 = 0. Answer: C] To enter a basis into WeBWorK, place the entries of each vector inside of brackets, and enter a list of 1 1 these vectors, separated by commas. For instance, if your basis is 2 , 1 , then you would 3 1 enter [1 ,2,3],[1 ,1,1] into the answer blank