We have an expression and we know the values of those variables. Replace the variables in the expression with the respective values.
3x - y - 3z becomes 3(-2) - 1 - 3(-2)
Use the order of operations to solve.
Order of operations tells us that multiplication have a higher precedence than subtraction.
3(-2) - 1 - 3(-2) = -6 - 1 - (-6) = -6 - 1 + 6
Addition and subtraction have the same precedence. We solve them from left to right. This is also true for multiplication and division.
-6 - 1 + 6 = -7 + 6 = -1
So, -1 is the answer.
