要使(x-2)(x²-ax+b)乘积中不出现含有x一次项及二次项则a=___________b=___________
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要使(x-2)(x²-ax+b)乘积中不出现含有x一次项及二次项则a=___________b=___________
要使(x-2)(x²-ax+b)乘积中不出现含有x一次项及二次项则a=___________b=___________
要使(x-2)(x²-ax+b)乘积中不出现含有x一次项及二次项则a=___________b=___________
原式=x³+(-a-2)x²+(b+2a)x-2b
不含x和x²则他们的系数为0
所以-a-2=0
b+2a=0
所以
a=-2
b=-2a=4