What is the coefficient of z in the expression 3x + 2y + z?

the coefficient is 1. 1z = 1*z = z.

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.