Answer: D) 1
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Step-by-step explanation:
The -2 outside the first matrix multiplies to every item inside that first matrix.
So the x updates to -2x in the upper left corner.
That -2x adds to the 3 in the upper left corner of the second matrix. The sum -2x+3 must be equal to the value in the upper left corner of the third matrix.
Everything is focused on the upper left corner.
So we must solve -2x+3 = x
Doing so leads to...
-2x+3 = x
3 = x+2x
3 = 3x
3x = 3
x = 3/3
x = 1