(x^2 - x+1) (x^2 - x+z)=12

a,(x^2 - x+1) (x^2 - x+z)=12
b, 3y^3 - 7y^2 - 7y +3=0
c, x^2 +2y^2=4x+4y-6
(giúp mik vs ạ)