已知向量a→=x1,y1，b→=x2,y2,若|a→|=2,|b→|=3,a→·b→=-6，则x1+y1x2+y2的值为（）

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已知向量a→=x1,y1，b→=x2,y2,若|a→|=2,|b→|=3,a→·b→=-6，则

x
1
+
y
1
x
2
+
y
2

的值为（）

A： $\frac{2}{3}$

B： $- \frac{2}{3}$

C： $\frac{5}{6}$

D： $- \frac{5}{6}$

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B

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