x + 6 = x in math would be a Linear equation. Now in a question ther would be something that said x = whatever number x equals and then you could solve this question. Hope I helped Brainliest if satisfied :D

The equation is undefined; If we simplified the equation, we get: x + 6 = x 6 = 0 Of course, we know: 6 ≠ 0 So, we say the function is undefined; The function will be undefined when the value of y or f(x) cannot be rearranged and solve to give a value of x; The function will have a vertical asymptote at this value of y or f(x); Similarly, a function will be undefined when a value of x is substituted and results in an equation similar to 6 = 0, i.e. one that we know is most definitely false/impossible; In this case, the function will have a horizontal asymptote at such a value of x.