`(x-2 )/ (x-4) -1 /( x-2) +2`
`= (x-2)^2/((x-4)(x-2)) - (x-4 )/ ((x-2)(x-4)) + (2(x-2)(x-4))/((x-2)(x-4))`
`=(x^2-4x+4-x+4+2x^2-8x-4x+16 )/ ((x-2)(x-4))`
`=(3x^2-17x+24) / ((x-2)(x-4))`
`=((3x-8)(x-3))/((x-2)(x-4))`
`(x-2) /( x+3) - (x+1)/(3-x) - (2x^2+6 )/(x^2-9)`
`=((x-2)(x-3))/((x+3)(x-3) )+ ((x+1)(x+3))/((x-3)(x+3)) -( 2x^2+6)/((x-3)(x+3))`
`=(x^2-3x-2x+6+x^2+3x+x+3-2x^2+6 )/( (x-3)(x+3))`
`=(-x+15 )/ ((x-3)(x+3))`
