`#DyHungg`
`a) ((x+2)/(x²+2x+1)+(x-2)/(1-x²))xx(x+1)/x`
`=(((x+2)(x-1)-(x-2)(x+1))/((x+1)²(x-1)))xx(x+1)/x`
`=((x²-x+2x-2-x²-x+2x+2)/((x+1)²(x-1)))xx(x+1)/x`
`=(2x)/((x+1)²(x-1))xx(x+1)/x`
`=2/(x²-1)`
Bài 2:
`a) (x-5)²+(x+3)²=2(x-4)(x+4)-5x+7`
`⇔x²-10x+25+x²+6x+9=2(x²-16)-5x+7`
`⇔x²+x²-2x²-10x+6x+5x=-25-9+7-32`
`⇔x=-59`
Vậy `S={-59}`
