Cześć!
[tex]W(x)=7x^3-3kx^2-x+2\\\\W(-1)=7\cdot (-1)^3 -3k\cdot (-1)^2 - (-1)+2 = 7(-1) -3k \cdot 1 +1+2 = -7-3k+3\\\\W(-1) = -4-3k[/tex]
Pozdrawiam!
