To evaluate the expression 9 + 3 x 2^2 - 1 x 4, you should follow the order of operations (PEMDAS/BODMAS).
First, perform the exponentiation:
2^2 = 4.
Now, perform the multiplication:
3 x 4 = 12.
Next, perform the multiplication:
1 x 4 = 4.
Now, perform the addition and subtraction from left to right:
9 + 12 - 4 = 21.
So, the value of the expression 9 + 3 x 2^2 - 1 x 4 is 21.
