Question

$\frac{a+b}{(b-c)(c-a)}+ \frac{b+c}{(c-a)(a-b)}+ \frac{c+a}{(a-b)(b-c)}$
$1- \frac{a}{1+ \frac{1}{1- \frac{1}{1+ \frac{1}{a} } } }$=

Answer 1

1
=[(a+b)(a-b)+(b+c)(b-c)+(c+a)(c-a)]/(b-c)(c-a)(a-b)=
=(a²-b²+b²-c²+c²-a²)/(b-c)(c-a)(a-b)=0/(b-c)(c-a)(a-b)=0
2
1)1+1/a=(a+1)/a
2)1:(a+1)/a=a/(a+1)
3)1-a/(a+1)=(a+1-a)/(a+1)=1/(a+1)
4)1:1/(a+1)=a+1
5)1+a+1=a+2
6)a:(a+2)=a/(a+2)
7)1-a/(a+2)=(a+2-a)/(a+2)=3/(a+2)