Looking for method to simplify equation within MATLAB

Say i have the equation where . I am looking for a way to simplify this equation to express X in terms of and c. through matlab, in a scaleable manner.

Answer 1

[Torsten]

syms a b c d
X = 2*a+3*b+7*c+d;
X = subs(X,d,2*a+4*b)

[Joe Read]

Thanks so much, very helpful