Question

please solve this step by step ​

Answer 1

You can solve this question by letting components of  vector c ,be x,y and z. And just put it in the given equation you will obtain three equations by solving which you will have values of x,y and z.Thus calculate |c| and just square it. The thing which you should take into consideration it tha in equation where a×c + b =0 ,here zero represent the zero vector in which the scaler component of vector are zero.