已知集合A=﹛χ|χ²+3χ-4=0﹜,B=﹛χ²+﹙a+1﹚χ-a-2=0﹜,

已知集合A=﹛χ|χ²+3χ-4=0﹜,B=﹛χ²+﹙a+1﹚χ-a-2=0﹜,

x^2+3x-4=0(x+4)(x-1)=0A={-4,1}x^2+(a+1)x-a-2=0(x+a+2)(x-1)=0x=-a-2或x=1A∪B=A,则B是A的子集因为X^2+（a+1）X-a-2=0有解x=1,B={1}时,x=-a-2=1a=-3B={-4,1}时,x=-a-2=-4a=2======以下答案可供参考======供参考答案1:A={-4,1},A∪B=A,A为空集或{1}或{-4} A为空集，(a+1)²+4(a+2）A为{1}或{-4}，代入即可供参考答案2:x^2+3x-4=(x+4)(x-1)=0则A={-4,1}x^2+(a+1)x-a-2=(x+a+2)(x-1)=0解得x=-a-2或x=1A∪B=A,则B是A的子集而A={-4,1}故有B={1}时,x=-a-2=1a=-3B={-4,1}时,x=-a-2=-4a=2供参考答案3:123供参考答案4:A: (x-1)(x+4) = 0 x = 1,x = -4B: x+a+2)(x-1) = 0 x = 1, x = - a- 2又A∪B=A 则 -a -2 = - 4 或 -a -2 = 1a = 2 或 a = 3供参考答案5:A={-4,1}∵A∪B=A∴B是A的子集x²+(a+1)x-a-2=0(x+a+2)(x-1)=0x=-a-2或x=1∵B是A的子集∴-a-2=1或-4∴a=3或2∴实数a的值为2或3

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