1) 7a/(x-3)•(x+3) + 5a/x-3 + a/x+3
7a+5a•(x+3)+a•(x-3)/(x-3)•(x+3)
7a+5ax+15a+ax-3a/(x-3)•(x+3)
19a+6ax/(x-3)•(x+3)
2) 4/x+2 + 3/x-2 - x+2/(x-2)•(x+2)
4/x+2 + 3/x-2 - 1/x-2
4(x-2)+3(x+2)-(x+2)/(x+2)•(x-2)
4x-8+3x+6-x-2/(x+2)•(x-2)
6x-4/(x+2)•(x-2)
3) a/1-b - a/1+b + a/(1-b)•(1+b)
a•(1+b)-a•(1-b)+a/(1-b)•(1+b)
a+ab-a+ab+a/(1-b)•(1+b)
2ab+a/(1-b)•(1+b)
4) 1/a+2 + 1/a-2 - 4/(a-2)•(a+2)
a-2+a+2-4/(a-2)•(a+2)
2a-4/(a-2)•(a+2)
2(a-2)/(a-2)•(a+2)
2/a+2