There are 2×2×2×2×2×2 = 2⁶ = 64 possible settings.
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Each switch can be in 2 positions, and for each of those, the other switches can have all possible settings. 1 switch has 2 settings. 2 switches will have 2×2 settings. 3 switches will have 2×2×2 settings.
I think that the answer is C.11
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Firstly you have to reduce the 4 variables to a double system of equation with only 2 variables.
Let's say, first we have to eliminate Z:
Take 1st & 3rd equation & multiply each term of the 1st by (- 1). One done you add up the 1st & the 3rd & you will get:
5W - 4x + 2y = - 18
Follow the same methodology to find another equation without z. Once done you will have a system of 2 equation with 2 variable easy to solve,
At the end you will find:
w = -3
x = -2
y = -1
z = 3
Answer:
no habla español
Step-by-step explanation:

Step-by-step explanation:

Let 
Then 
or

This gives us
or all integer multiples of 