1) (a-4b)^2-8ab-17b 2) -9c^2+(3c+b)^2-b^2 3) (5a-6)^2-(5a-6)(5a+6) - вопрос №85519961428172923223562565647 от dilnuscha 25.03.2020 12:28

Question

Алгебра: 1) (a-4b)^2-8ab-17b 2) -9c^2+(3c+b)^2-b^2 3) (5a-6)^2-(5a-6)(5a+6) 4) (7b-t)(t+7b)+(7b+t)^2 5) (9-8b)(2b+3)+(4b-1)^2 6) (11c+3)^2-2c(5,5c+33)

dilnuscha · Answer

1) (а-4b)²-8ab-17b=(a²-2•a•4b+4b²)-8ab-17b=a²-8ab+4b²-8ab-17b=a²+4b²-17b
2)-9c²+(3c+b)²-b²=-9c²+(9c²+2•3c•b+b²)-b²=-9c²+9c²+6bc+b²-b²=6bc
3) (5a-6)²-(5a-6)(5a+6)=(5a-6)²-(5a-6)²=0