(5a+2b)²+(5a-2b)²-2(5a+2b)(2b-5a)- (20a-3)(5a+2)+5(5a-7)=
= (25a²+10ab+4b²+25a²-10ab+4b²) - 2(4b²-25a²)-(100a²+40a-15a-6)+(25a-35)=
= 50a²+8b²-8b²+50a²-100a²-25a+6+25a-35=
= 6-35= -29
Для недоверчивых, проверим на простых числах а=1, b=2
(5+4)²+(5-4)²-2(5+4)(4-5)-(20-3)(5+2)+5(5-7)=
=81+1-2*9*(-1) -17*7+5*(-2)=
=82+18-119-10=100-129=-29