Can someone help me find the solution for these two quadratic equations ?
$ 2(z^2) \ - \ 3.023bz \ + \ 0.115(b^2) \ + \ 2.0814b \ + \ 0.142z \ - \ 0.5856 \ = \ 0 $
$ 6.0828(z^2) \ + \ 2.0414bz \ + \ 1.0207(b^2) \ - \ 1.0345b \ - \ 4.0836z \ + \ 1.048 \ = \ 0 $
It is kind of tricky solving a multidimensional non-linear equation, i.e. a non-linear system of algebraic equations.
If you want to solve numerically, you can apply some iterative procedure like bisection method or Newton method to find roots numerically. You can find more information (along with the code) here: http://dml.cz/bitstream/handle/10338.dmlcz/104332/AplMat_34-1989-1_3.pdf
Let me know if you need help with the implementation.