помогите пожалуйста очень срочно АЛГЕБРА​

Объяснение:

1)

(m+10)/(9-m²) - (m+1)/(9-m²)=

=(m+10-m-1)/(9-m²)=9/(9-m²)

2)

(3y+7)/(4-y) + (y+15)/(y-4)=

= -(3y+7)/(y-4) +(y+15)/(y-4)=

= (-3y-7+y+15)/(y-4)=(-2y+8)/(y-4)=

=( -2(y-4))/(y-4)= -2

3)

7/(9ab) - 13/(12ab)= ((7•4)-(13•3))/(36ab)=

=(28-39)/(36ab)= -11/(36ab)

4)

(2m-5n)/m - (6n²-5m²)/mn=

=(n(2m-5n) -6n²+5m²))/mn=

=(2mn-5n²-6n²+5m²)/mn=

=(2mn-11n²+5m²)/mn

5)

6a/(5xy) + 4b/(3xy²) - 7/(4x²y)=

=(6a•12xy+4b•20x-7•15y)/(60x²y²)=

=(72xya+80xb-105y)/(60x²y²)