Выражение 2)12*p^3-1/3*p^2-1-3*p*3/3*p^2; 4)5*x+1/5*x-20+x+17/20-5*x; 6)64-2*a*b/ (a-8)^2+2*a*b-a^2/ (8-a)^2; 8)x^2+6/x^2-9-3*(2*x-1)/9-x^2

2) 12p³-(1/3)p²-1-3p×(3/3)×p²=

=12p³-(1/3)p²-1-3p×1p²=

=12p³-(1/3)p²-1-3p³=9p³-(1/3)p²-1=

=(1/3)(27p³-p²-3)

4) 5x+(1/5)x-20+x+(17/20)-5x=

=(1/5)x-20+x+(17/20)=(6/5)x-(383/20)=

=1/20(24x-383)

6) 64-(2ab/(a-8)²)+2ab-(a²/(8-a)²)=

=64-(2ab/(a-8)²)+2ab-(a²/(-(a-8))²)=

64-(2ab/(a-8)²)+2ab-(a²/(a-8)²)=

64(a²-16a+64)-2ab+2a³b-32a²b+128ab

-a²/(a-8)²=

63a²-1024a+4096+126ab+2a³b-32a²b/(a-8)²

Больше никак не сократить!

8) x²+(6/x²)-9-(3(2x-1)/9)-x²=

=(6/x²)-9-((2x-1)/3)=

=(18-27x²-x²(2x-1))/3x²)=

=((18-27x²-2x³+x²)/3x²)=

=((-2x³-26x²+18)/3x²)