题目内容
对于任意的两个实数对 (a,b) 和 (c,d),规定:(a,b) = (c,d)当且仅当a = c,b = d;运算“?”为:(a,b) ? (c,d) = (ac+bd,bc-ad);运算“?”为:(a,b) ? (c,d) = (a + c,b + d),设x ,y? R,若(3,4) ? (x ,y) = (11,-2),则(3,4) ? (x ,y) =
- A.(4,6)
- B.(4,6)
- C.(2,2)
- D.(5,5)
B
由(3,4); (x ,y) = (11,-2)可得3 x +4 y =11且4 x-3 y =-2,解得x =1,y =2;所以(3,4) Å (x ,y)=(4,6).
由(3,4); (x ,y) = (11,-2)可得3 x +4 y =11且4 x-3 y =-2,解得x =1,y =2;所以(3,4) Å (x ,y)=(4,6).
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