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(x-1)/(x+4)-(x+1)/(4-x)-(8x+8)/(x^2-16)
题目详情
(x-1)/(x+4)-(x+1)/(4-x)-(8x+8)/(x^2-16)
▼优质解答
答案和解析
(x-1)/(x+4)-(x+1)/(4-x)-(8x+8)/(x^2-16)
=(x-1)/(x+4)+(x+1)/(x-4)-[8(x+1)]/[(x-4)(x+4)]
=[(x-1)(x-4)+(x+1)(x+4)-8(x+1)]/[(x-4)(x+4)]
=[(x-1)(x-4)+(x+1)(x+4)-8(x+1)]/[(x-4)(x+4)]
=(2x^2-8x)/[(x-4)(x+4)]
=2x/(x+4)
=(x-1)/(x+4)+(x+1)/(x-4)-[8(x+1)]/[(x-4)(x+4)]
=[(x-1)(x-4)+(x+1)(x+4)-8(x+1)]/[(x-4)(x+4)]
=[(x-1)(x-4)+(x+1)(x+4)-8(x+1)]/[(x-4)(x+4)]
=(2x^2-8x)/[(x-4)(x+4)]
=2x/(x+4)
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