How to plot the sum of two functions using stem function

 X[n]=[1,-2,4,6,-5,8,10]

Generate and plote samples using stem function

 Y[n] =3x[n+2] +x[n-4]+2x[n]

[Walter Roberson]

An initialization is given for X[n] . Is each X[n] intended to be a vector? Or is the intention that X[1] = 1, X[2] = -2, and so on?

Is there a formula given for further values of X[n], or should we consider X[n] to be that vector and X[n+2] (for example) to also be that vector?

We are given a formula for Y[n] in terms of x values. Is there a relationship between the X values that were defined in the first line and the x that is used in the second line?