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[(4x+12)/(x^2-2x-8)]/[(9x+8)/(x+2)-x^2+2x-4)
题目详情
[(4x+12)/(x^2-2x-8)]/[(9x+8)/(x+2)-x^2+2x-4)
▼优质解答
答案和解析
=4(x+3)/(x-4)(x+2) ÷[(9x+8)/(x+2)-(x²-2x+4)(x+2)/(x+2)]
=4(x+3)/(x-4)(x+2) ÷[(9x+8-x³-8)/(x+2)]
=4(x+3)/(x-4)(x+2) ÷[(9x-x³)/(x+2)]
=4(x+3)/(x-4)(x+2) ×(x+2)/[-x(x+3)(x-3)]
=-4/x(x-4)(x-3)
=4(x+3)/(x-4)(x+2) ÷[(9x+8-x³-8)/(x+2)]
=4(x+3)/(x-4)(x+2) ÷[(9x-x³)/(x+2)]
=4(x+3)/(x-4)(x+2) ×(x+2)/[-x(x+3)(x-3)]
=-4/x(x-4)(x-3)
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