`#AkaShi`
`a) (x^2-2)/(x^2-4x)+3/(x-4)+7/(5x) ` ( Đk: `x \ne 4 ; x \ne 0` )
`=(x^2-2)/(x(x-4))+3/(x-4)+7/(5x)`
`=(5(x^2-2))/(5x(x-4))+(15x)/(5x(x-4))+(7(x-4))/(5x(x-4))`
`=(5x^2-10+15x+7x-28)/(5x(x-4))`
`=(5x^2+22x-38)/(5x(x-4))`
........................
`6/(x^2-3x+2)+(2x-2)/(x^2-4)`
`=6/(x^2-x-2x+2)+(2x-2)/(x^2-4)`
`=6/((x-1)(x-2))+(2x-2)/((x-2)(x+2))`
`=(6(x+2))/((x-1)(x-2)(x+2))+((2x-2)(x-2))/((x-2)(x+2)(x-1))`
`=(6x+12+2x^2-6x-4)/((x-2)(x+2)(x-1))`
`=(2x^2+8)/((x-2)(x+2)(x-1))`
