= 7/[2(x-2)]-3/(x+2)+ 12/[(2+x)(2-x)]

= 7/[2 (x-2)]-3/(x+2)-12/[(x+2) (x-2)], and the lowest common denominator is 2(x+2)(x-2).

= 7(x+2)/[2(x+2)(x-2)]-3×2(x-2)/[2(x+2)(x-2)] 12×2/[2(x+2)(x-2)]

=[7(x+2)-6(x-2)-24]/[2(x+2)(x-2)]

=(7x+ 14-6x+ 12-24)/[2(x+2)(x-2)]

=(x+2)/[2(x+2)(x-2)]

= 1/(2x-4)