The answer is B, see how to calculate it
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x=5+2y
-3(5+2y)+2y=7 ///put things from the first equation into the second one
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x=5+2y
-15-6y+2y=7 ///reduce
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x=5+2y
-4y=7+15 /// move everything without y into right side
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x=5+2y
-4y=22 ////reduce
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x=5+2y
y=-11/2 ///dive by what stands
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x=5+2*(-11/2)
y=-11/2
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x=-6
y=-11/2
