x²+4x+4分之1-x²÷（x+1）²乘以x-1分之x²+3x+2 =（x+2)²（x+1）²分之(x+1)²-x²乘以x-1分之（x+1）(x+2)=（x+2)²（x+1）²分之2x+1乘以x-1分之（x+1）(x+2)=（x
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