In illustration 21 i am getting for part (-1,-1,33/7) but answer they say answer is (-3/7,-1,33/7), similarly for second part i am getting (-25,23,-9) but they say answer is (-21,23,-9). Who is correct?
You're correct bro. There is definetly an error in the book.
P.S. You should trust your multiplication, addition and division.