9. Le tf(x) be a polynomial of degree 6 in x, in which the coefficient of x6 is unity and it has f(x) extrema at x= -1 and x = 1. If lim=1, then 5 f(2) is equal to.................. 10. If the system of equations kx + y + 2z=1 3x-y-2z=2 -2x-2y-4z=3 0