Calculate multivariable equation with Matlab

I am trying to calculate the voltage of a circuit with an ADC, the problem is that I am seeing that the voltage reading has to be done from a function and that it depends on the current of the circuit, I arrived at the following equations for 0A, 0.4 A and 1.1A:

0A: 0.10680454x - 7.6688459

0.4A: 0.10669344x - 13.84042838

1.1A: 0.10652463x - 24.9126498

How can I put this together into an equation with two variables One for the voltage reading and one for the amperage.

Thank you so much!

Here is a plot of how the amperaje affects the votlage reading

Answer 1

[Catalytic]

You need some sort of model for the line slopes and intercepts as a function of the amperage. There are infinitely many that can be proposed. For example -

x0=[0,0.4,1.1];
y0=[0.10680454 0.10680454 0.10652463;
    7.6688459 13.84042838 24.9126498];

voltage=@(A,x) voltageFcn(A,x, x0,y0);


function v=voltageFcn(A,x, x0,y0)
 p=spline(x0,y0,A);
 v=p(1)*x+p(2);
end