Question

Помогите пожалуйста

Тема: "Сложение и вычитание дробей с разными знаменателями".

Представьте в виде дроби:

1)5/x + 6/y=

2)9/x - 5/xy=

3)4/12ab - 11/18ab=

4)5m/3ab - 7n/5a²b=

5)3x-1/x² + x-9/3x=

6)1/2ab² - 1/6a²=

7)3b+7/3b - b²-5/b²=

8)y/4+y - 2/5=

9)c+3/c² - 1/c=

10)x-y/x² - y-x/xy=

11)3x+2/5x - 5x+3y/10xy - y-1/2y=

12)(a-b)²/18b - (a-b)²/12b=

13)6y + 1/y=

Answer 1

Ответ:

Объяснение:

1) 5/x + 6/y= (5y + 6x)/(xy)

2) 9/x - 5/xy= (9y - 5)/(xy)

3) 4/12ab - 11/18ab= (4*3 - 11*2)/(36ab) = -10/(36ab) = -5/(18ab)

4) 5m/3ab - 7n/5a²b= (5m*5a - 7n*3)/(15a^2*b) = (25am - 21n)/(15a^2*b)

5) (3x-1)/x² + (x-9)/3x= (3(3x-1) + x(x-9))/(3x^2) =

= (9x - 3 + x^2 - 9x)/(3x^2) = (x^2 - 3)/(3x^2)

6) 1/2ab² - 1/6a²= (3a - b^2)/(6a^2*b^2)

7) (3b+7)/3b - (b²-5)/b²= (b(3b+7) - 3(b^2 - 5))/(3b^2) =

= (3b^2 + 7b - 3b^2 + 15)/(3b^2) = (7b + 15)/(3b^2)

8) y/4+y - 2/5= (5y - 2(4+y))/(5(4+y)) = (5y-8-2y)/(20+5y) = (3y-8)/(5y+20)

9) c+3/c² - 1/c= (c+3 - c)/c^2 = 3/c^2

10) (x-y)/x² - (y-x)/xy= (y(x-y) - x(y-x))/(x^2*y) =

= (xy - y^2 - xy + x^2)/(x^2*y) = (x^2 - y^2)/(x^2*y)

11) (3x+2)/5x - (5x+3y)/10xy - (y-1)/2y= (2y(3x+2) - (5x+3y) - 5x(y-1))/(10xy) =

= (6xy+4y-5x-3y-5xy+5x)/(10xy) = (xy+y)/(10xy) = y(x+1)/(10xy) = (x+1)/(10x)

12) (a-b)²/18b - (a-b)²/12b= (2(a-b)^2 - 3(a-b)^2)/(36b) = -(a-b)^2/(36b)

13) 6y + 1/y= (6y^2 + 1)/y