You are given the expression 3x + 2y + z
It is clear that coefficient of x is 3 and y is 2. But there is nothing written with z.
So what is the coefficient of z?
When there is no number written before a variable, then its coefficient is 1.
Coefficient is always muktiplied with the variable. So z = 1×z = 1z. But we generally do not write 1 before a variable.
So coefficient of z is 1.