(x+1)/(x-1)－4/5＜0[5(x+1)]/[5(x-1)]－[4(x-1)]/[5(x-1)]＜0[(5x+5)－(4x-4)]/[5(x-1)]＜0(x+9)/[5(x-1)]﹤0∴不等式的解集是(-9，1)
