# Help need in Mathematica or Sage

I want to find the common positive solutions of two polynomials $f_{a,b}(x,y)$, $g_{a,b}(x,y)$ where $a,b$ runs from 0 to 1 with an interval 0.01. Let $(x_0,y_0)$ be a common positive solution. Then I want evaluate a third polynomial $h_{a,b}(x_0,y_0)$. If this value is less than zero, I will change $b$ accordingly.

I have this tried in Mathamatica but could not succeed as follows: b=0 For[$a=0,a<1,a=a+0.01$, Solve[{$x^2$-$ax$+$by$==0, $2xa+y^2-5ab==0$},{$x,y$}]].

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