MATLAB: How do rewrite a variable with the symbolic toolbox

Question

Hi,

I have a question about the symbolic toolbox. When I use simple relations, I cannot rewrite a variable in another variable. here is an example:

syms a b
a=b+3
solve(a,b)

This leads however to -3, which means that solve assumes that a is 0? I would like an output like b=a-3. If I do this in another way using solve, solve cannot find a solution:

syms a b
a==b+3
solve(a,b)

Does anyone have an idea how I can find b=a-3? It isn't necessary to use solve, but I couldn't think of another way. Thanks in advance!

Answer 1

syms a b
eq=a==b+3
isolate(eq,b)
%or
b=solve(eq,b)