# Is $y(t) = \cos(t) + x(t)$ a time-invariant system?

Is $$y(t) = \cos(t) + x(t)$$ a time-invariant system?

$$y(t-k) = \cos(t-k) + x(t-k)$$

But it isn't equal to $$\cos(t) + x(t-k)$$

So, would it be time-invariant?