2)a) =10m^2-13mn-3n^2-10m^2-20mn-10n^2=
=-33mn-13n^2
б)=-27а^6b^9*4a^10b^2=-108a^16b^11
1)(3(5x-1)-4(x-2))/12=12(10-x)/12
(15x-3-4x+8-120+12x)/12=0 |:12
23x-115=0
23x=115
x=5
