yea that's what i did before but it didn't give me an answer.it just keeps itself busy for ages but give no solutions in the end. For the last simultatenous eqn, my ti 89 titanium doesn't even attempt to sove it: it just says ''false''...that's the answer it gives. too bad.i can solve them using the traditional method of pen and paper, but it takes long time to find the solutions, esp for the last(ie the one containing a non-linear equation.) but time is money.i bought ti 89 to calculate such equations, but it just turned out to be of no help.well casio all the way!.
Thanks you very much for offering help.it's appreciated.