How to plot multivariable functions against each other?

Have defined to functions based on biological mechanisms and am trying to plot the two against each other (GF on the x-axis, ECM on y-axis) where the variables in the equations (x and y) are the possible concentrations of the molecules which are reactants. The rest of the constants are defined. For some reason I cannot find a way to plot them?

% Variable Initialization
x = linspace(0,10);
y = linspace(0,10);

% Parameters
v2fak = 0.05; v1fak = 0.04; k2fak = 0.1; k1fak = 0.1; fakt = 1;
kagf = 0.1; kdap1 = 0.15; vs2ap1 = 0.05; kafak = 0.1; vsap1 = 0.05;

GF = [kagf * (kdap1 * x - vs2ap1 * (y / (kafak + y)))] / [vsap1 + vs2ap1 * ...
    (y / (kafak + y)) - kdap1 * x];

ECM = (v2fak / v1fak) * (y / (k2fak + y)) * (k1fak + (fakt - y)) / ...
    (fakt - y) - [kagf * (kdap1 * x - vs2ap1 * (y / (kafak + y)))] / [vsap1 + vs2ap1 * ...
    (y / (kafak + y)) - kdap1 * x];

plot(GF,ECM);

Answer 1

[Star Strider]

Vectorize all the vector multiplications and divisions, and it works:

GF = (kagf * (kdap1 * x - vs2ap1 * (y / (kafak + y)))) ./ (vsap1 + vs2ap1 * ...
    (y / (kafak + y)) - kdap1 * x);

ECM = (v2fak / v1fak) * (y ./ (k2fak + y)) .* (k1fak + (fakt - y)) ./ ...
    (fakt - y) - (kagf * (kdap1 * x - vs2ap1 * (y ./ (kafak + y)))) ./ (vsap1 + vs2ap1 * ...
    (y ./ (kafak + y)) - kdap1 * x);

Also, use parentheses instead of square brackets unless you intend to define matrices with individual elements.