(i) The coefficient of x2 in π6x+x2−1 is 1.
(ii) The coefficient of x2 in 3x- 5 is 0.
(iii) Let p(x)=(x−1)(3x−4)=3x2−4x−3x+4=3x2−7x+4
Hence, the coefficient of x2 in p(x) is 3.
(iv) Let p(x)=(2x−5)(2x2−3x+1)=2x(2x2−3x+1)−5(2x2−3x+1)=4x3−6x2+2x−10x2+15x−5=4x3−16x2+17x−5
Hence, the coefficient of x2 in p(x) is -16.