1)=-6c^5(c-1)(c^2+c+1)
2)=5(-3ab+1)(a+b)(a-b)
3)=4xy^2-36x+4x^2y^2-36x^2-9+y^2
4) =-(5y+6x^2+10)(5y+6x^2-10)
1) x=0,x=-1 / 7
2) x=0,:x=-1,x=1
