Solving Coupled First Order ODE dependent on Derivatives

I'm trying to use ODE45 to solve a similar differential equation to the following. I'm not sure how to write the function though.

My functions are on the left and on the write is what I would have in the matlab function file, but how do I reference y' and x'? If I try using bprime(1) and bprime(2) I get an error because I'm using them before defining them.

My file would look something like this:

function bprime = dynamicEqs(t,b)
bprime = [3*___ + b(1); ___ -2*b(2)];
end

Thanks so much

Answer 1

[Torsten]

Write your equations as

[1  -3; -1 1]*[x' y'] = [x -2*y]

and use the mass matrix option of ODE45.

Best wishes

Torsten.

Answer 2

[Jan]

Or aftzer multiplying by inv([1 -3; -1 1]):

dx = -0.5*x + 3*y;
dy = -0.5*x + y;

Answer 3

[Benjamin Czerwin]

Thanks guys!