1)5^3*5^2=5^5; 3^8:3^6=3^2; (2^3)^4=2^12=; 3^5*2^5=6^5;
2)3b+c^2-d-c^2+2d=3b+d
3)(-0,25a^3b^2c)*(5abc)=-0.5a^2b
(7m^2-20mn-10m):10m=m(7m-20n-10):10m=7m-20n-10/10 (дальше не знаю)
4)2m^2-2m+m^2+2m-2m-4+2m=3m^2+2m-4=3*(-0,0625)-0,5-4=-0,1875-4,5=-4,6875