Question 19228
first one...find x in terms of y from the second equation, then sub this into equations 1 and 3 to end up with 2 other equations in just y and z. Then solve these 2 as normal.


As for the 4 equations in 4 unknowns...honestly, i would cry if i was you. You need Gaussian Elimination or Cramer's rule (if you can do 4x4 determinants!). Good luck!  Look into the Lessons on this website, there are a few there that should help you.


Jon