Выражение: 1) (m+4)^2-(m-3)(m+3) 2) 3(b-1)^2+8b - вопрос №337179414233231283527428 от стас483 19.05.2021 07:32

Question

Алгебра: Выражение: 1) (m+4)^2-(m-3)(m+3) 2) 3(b-1)^2+8b 3) (n+5)^2-n(n-7) 4) 2c(8c-3) -( 4c+1)^2

стас483 · Answer

1) (m+4)²-(m-3)(m+3) = (m²+2·4·m+16)-(m²-3²)=m²+8m+16-m²+9=8m+25
2) 3(b-1)²+8b = 3(b²-2b+1)+8b=3b²-6b+3+8b=3b²+2b+3
3) (n+5)²-n(n-7) = n²+10n+25-n²+7n=17n+25
4) 2c(8c-3) -( 4c+1)²=16c²-6c-((4c)²+2·4c·1+1²)=16c²-6c-(16c²+8c+1)=
16c²-6c-16c²-8c-1=-14c-1