Solve Function - Having Difficulties

I'm having trouble using the solve function and I don't understand the problem. I looked at other posts + documentation but I still don't see it.

>> x = solve('x+4==2',x)
Error using solve>getEqns (line 418)
List of equations must not be empty.
Error in solve (line 226)
[eqns,vars,options] = getEqns(varargin{:}); 

This is the input I entered and the error I'm receiving.

Answer 1

[Stephan]

syms x
xsol = solve(str2sym('x+4==2'),x)

[SJ Won]

What's the reason people use quotes for the mathematical expression? Isn't it easier just using x+4==2 ?

Answer 2

[Vaibhav Tomar]

Quotes are necessary as it's a string.

You need to use str2sym

str2sym(symstr) evaluates symstr where symstr is a string representing a symbolic expression. Enter symbolic expressions as strings only when reading expressions from text files or when specifying numbers exactly. Otherwise, do not use strings for symbolic input.

Use:

x=sym('x')
solx= solve(str2sym('x+4==2'),x)