1.а) 12х^3 - 27ху^2=3х (4х^2 - 9у^2)=3х (2х-3у)(2х+3у)
б) = 2 (а^3-8b^3)=2 (a-2b)(a^2+2b+4b^2)
в) = m (m^4 - 8m^2 n + 16n^2) = m (m^2 - 4n)^2
г) = (9х^2 - 25у^2) + (15х+25у) =(3х-5у)(3х+5у) + 5 (3х+5у)=(3х-5у+5)(3х+5у)
2. = а^3 + а^2 - а^2 - а- а^3 + 8= -а+8
-3 3/4 + 8 = (-15+32)/4=17/4=4 1/4
3. -(3х-1)^2 + 2 (5+х)(х-5) + 7х^2 = 3
-9х^2+6х-1+2х^2-50+7х^2=3
6х=54
х=9