1/a+1/b=5
(a+b)/(ab)=5
(2a-5ab+2b)/(-a+3ab-b)
=(2/b-5+2/a)/(-1/b+3-1/a)
=[(2a+2b)/(ab)-5]/[-(1/a+1/b)+3]
=(10-5)/(-2)
=5/(-2)
=-5/2
1/a+1/b=5
(a+b)/(ab)=5
(2a-5ab+2b)/(-a+3ab-b)
=(2/b-5+2/a)/(-1/b+3-1/a)
=[(2a+2b)/(ab)-5]/[-(1/a+1/b)+3]
=(10-5)/(-2)
=5/(-2)
=-5/2