= 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)