ganz ausführliche Berechnung:
2b2 - 53b-5(b-3)(b-4)-(6(b-5)-3(b+4)2)
= 2b2-53b-5(b-3)*(b-4)-(6(b-5)-3(b+4)2)
= 2b2-53b-5(b-3)*(b-4)-(6(b-5)-3(b+4)*(b+4))
= 2b2-53b-5((b2-4b)-(3b-12))-(6(b-5)-3(b+4)*(b+4))
= 2b2-53b-5((b2-4b)-(3b-12))-(6(b-5)-3((b2+4b)+(4b+16)))
= 2b2-53b-5(b2-4b-3b+12)-(6(b-5)-3((b2+4b)+(4b+16)))
= 2b2-53b-5(b2-7b+12)-(6(b-5)-3((b2+4b)+(4b+16)))
= 2b2-53b-(5b2-35b+60)-(6(b-5)-3((b2+4b)+(4b+16)))
= 2b2-53b-(5b2-35b+60)-((6b-30)-3((b2+4b)+(4b+16)))
= 2b2-53b-(5b2-35b+60)-((6b-30)-3(b2+4b+4b+16))
= 2b2-53b-(5b2-35b+60)-((6b-30)-3(b2+8b+16))
= 2b2-53b-(5b2-35b+60)-((6b-30)-(3b2+24b+48))
= 2b2-53b-(5b2-35b+60)-(6b-30-3b2-24b-48)
= 2b2-53b-(5b2-35b+60)-(-18b-78-3b2)
= 2b2-53b-5b2+35b-60+18b+78+3b2
= 18