Ich hoffe, das ist wie folgt verständlich:
0 + [1/4·a·x^4 + 1/3·b·x^3 + 1/2·c·x^2]-20 + [1/2·x^2 - 2/9·x^3]02/3 + 0
= [1/4·a·x^4 + 1/3·b·x^3 + 1/2·c·x^2]-20 + [1/2·x^2 - 2/9·x^3]02/3
= (1/4·a·0^4 + 1/3·b·0^3 + 1/2·c·0^2) - (1/4·a·(-2)^4 + 1/3·b·(-2)^3 + 1/2·c·(-2)^2) + (1/2·(2/3)^2 - 2/9·(2/3)^3) - (1/2·0^2 - 2/9·0^3)
= - (1/4·a·(-2)^4 + 1/3·b·(-2)^3 + 1/2·c·(-2)^2) + (1/2·(2/3)^2 - 2/9·(2/3)^3)
= - (4·a - 8/3·b + 2·c) + (2/9 - 16/243)
= - 4·a + 8/3·b - 2·c + 38/243