i want to know if sumone does not know how to form equation of plane in cartesian form but in vector form he can do it any question in 3-d so if he does question given in cartesian form by changing it to vector form and gets a correct ans will he get full marks or marks will be deducted .........please answer as early as possible urgent

You can solve the question in any form unless specified. 

When you will convert cartesian form into vector form, it will take time and the solution will become lengthy.

So to save time for rest of the questions, prefer solving in the cartesian form only.

Go through our study material for better understanding and if you still face any problem, mention us the specific step.