(х-2/10/81х):(х-1/81х)=((х/10-0,2)/81х)*(81х/х-1)=(х/10-0,2)/(х-1), если х=1, то (1/10-0.2)/(1-1)=0
10/25=2/5
3/9=1/3
x^3/x^9=1/(x^6)
y^2/y^5=1/(y^3)
Ответ: 2/(15x^6*y^3)
1) 21-9x=-2.5x+8
-9x+2.5x=8-21
-6.5x=-13
x=2
y=21-9•2= 3 A(2;3)
2) 16.2+8x= -0.8x+7.4
8x+0.8x=7.4-16.2
8.8x=-8.8
x= -1
y= 16.2+8•(-1)= 8.2 A(-1;8.2)
(4,5y+9)-(6,2-3,1y)=7,2y+2,8
4,5y+9-6,2+3,1y=7,2y+2,8
7,6y+2,8=7,2y+2,8
0,4y=0
y=0