Question

Упростите выражения:
7a/a²-4b²-7/a-2b

(9y/x-49/y):(3y-7x)

Answer 1

7a/(a²-4b²)-7/(a-2b )=7a/(a-2b)(a+2b)-7/(a-2b)=(7a-7a-14b)/(a²-4b²)=
=-14b/(a²-4b²)=14b/(4b²-a²)

(9y/x-49x/y):(3y-7x)=(9y²-49x²)/xy:(3y-7x)=(3y-7x)(3y+7x)/xy*1/(3y-7x)=
=(3y+7x)/xy