Question

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Answer 1

а
[ab(a+b)+(a+b)]/(ab+1)=(a+b)(ab+1)/(ab+1)=a+b
б
[u(u+v)-2(v+u)]/(u-2)=(u+v)(u-2)/(u-2)=u=v
в
[2b(b-a)-s(b-a)]/[-2b(b+a)+s(b+a)]=(b-a)(2b-s)/[(b+a)(s-2b)]=
=-(b-a)/(b+a)=(a-b)/(b+a)