VECTOR PROBLEM..Find the normal and write the plane equation in scalar product form.PLEASE HELP!!!!!

Find the vector equation in scalar product of the plain that contains the lines
r=i+j+s(i+2j-k)
r=i+j+t(-i+j-2k)
i use the cross product on the direction vectors of the 2 lines and i get -3i+3j+3k
after doing the rest of the work my equation plane is r.(-3i+3j+3k)=0...the answer at the back of the book is r.(i-j-k)=0.....PLEASE HELPPP!!!I,ll reward 10 points straight away!!

I'm pretty sure that your answer is correct because it is a multiple of the answer given in the back of the book (there is no unique equation of a plane - think of the plane as being infinite, so it does not matter what the multiple of the equation is).

If you multiply both sides of the equation in your answer by -1/3, then you obtain the answer in the back of the book. So, your answer is equivalent to the book's answer.

I hope this helps!

The two answers are equivalent. Multiply both sides of your equation by (-1/3) to get the answer in the book.