5. Упростите выражение 5 x-7 + 2 x - 3x x² - 49 + 21 49 - حمير.

5/(x-7) + 2/x - (3x)/(x²-49) + 21/(49-x²) = 5/(x-7) + 2/x - (3x)/((x-7)(x+7)) - 21/((x-7)(x+7)) = (5x(x+7))/(x(x-7)(x+7)) + (2(x-7)(x+7))/(x(x-7)(x+7)) - (3x²)/(x(x-7)(x+7)) - (21x)/(x(x-7)(x+7)) = (5x²+35x+2(x²-49)-3x²-21x)/(x(x-7)(x+7)) = (5x²+35x+2x²-98-3x²-21x)/(x(x-7)(x+7)) = (4x²+14x-98)/(x(x-7)(x+7)) = (2(2x²+7x-49))/(x(x-7)(x+7)).

Ответ: (2(2x²+7x-49))/(x(x-7)(x+7))