A
1)(x+4)/3(x+1)-1/(x+1)=(x+4-3)/3(x+1)=(x+1)/3(x+1)=1/3
2)[(x+1)/3]^-1=3/(x+1)
3)1/3*3/(x+1)=1/(x+1)
4)1/(x+1)+2(x+1)(x-1)=(x-1+2)/(x-1)(x+1)=(x+1)/(x-1)(x+1)=1/(x-1)
b
1)(x+10)/5(x+5)-1/(x+5)=(x+10-5)/5(x+5)=(x+5)/5(x+5)=1/5
2)[(x-5)/5]^-1=5/(x-5)
3)1/5*5/(x-5)=1/(x-5)
4)1/(x-5)-10/9x-5)(x+5)=(x+5-10)/(x-5)(x+5)=(x-5)/(x+5)(x-5)=1/(x+5)