Выполните вычитание:
1) a-5/5a^3 - 1-a/a^4
2) 9/a - 18/a^2+2a
3) x^2/x^2-49 - x/x+7
4) 7b - 21b^2/3b+4

Предыдущий
вопрос Следующий
вопрос

1) (a - 5)/(5a^3) - 1 - a/(a^4)
= (a - 5)/(5a^3) - a/(a^4) - 1
= (a^4 - 5a^4)/(5a^3*a^4) - a/(a^4) - 1
= (-4a^4)/(5a^7) - a/(a^4) - 1
= -4/(5a^3) - 1/a - 1

2) 9/a - 18/(a^2+2a)
= 9/a - 18/(a(a+2))
= 9/a - 18/(a^2 + 2a)
= (9(a+2) - 18)/a(a+2)
= (9a + 18 - 18)/a(a+2)
= 9/a

3) x^2/(x^2-49) - x/(x+7)
= x^2/((x-7)(x+7)) - x/(x+7)
= x^2/((x-7)(x+7)) - (x(x-7))/((x-7)(x+7))
= (x^2 - x(x-7))/((x-7)(x+7))
= (x^2 - x^2 + 7x)/((x-7)(x+7))
= 7x/((x-7)(x+7))

4) 7b - 21b^2/(3b+4)
= 7b - 21b^2/(3b + 4)
= 7b - 21b^2/(3b + 4)
= 7b - (21b^2(3b + 4))/(3b + 4)
= 7b - 63b^3 - 84b^2/(3b + 4)