Ответ:
Объяснение:
7) (y²-16)/(3y+12)=((y-4)(y+4))/(3(y+4))=(y-4)/3
8) (5x-15y)/(x²-9y²)=(5(x-3y))/((x-3y)(x+3y))=5/(x+3y)
9) (c+2)²/(7c²+14c)=(c+2)²/(7c(c+2))=(c+2)/(7c)
10) (6cb-18c²)/(b-3c)²=(6c(b-3c))/(b-3c)²=(6c)/(b-3c)
11) (a+5)²/(a²-25)=(a+5)²/((a-5)(a+5))=(a+5)/(a-5)
12) (a³-b³)/(a-b)=((a-b)(a²+ab+b²))/(a-b)=a²+ab+b²