S=12/3600*210=21/30<span>км= 700</span>
Почему задание не написал(а)?!
1)...=z^2+4z-z-4=z^2+3z-4
(ЕСЛИ ДИСКРИМИНАНТ НАДО НАЙТИ, то
пиши следующее...
D=25
z(1)=(-3-5)/2=-4
z(2)=(-3+5)/2=1
Ответ: -4; 1.)
2)...=mn-m+6n-6
3)...=bc+5b+4c+20
По формуле разности квадратов <em>a² - b² = (a-b)(a+b)</em> :
![\tt (2a+p)^2-(2a-p)^2=(2a+p-(2a-p))(2a+p+2a-p)=\\\\=(2a+p-2a+p)(4a)=2p\cdot4a=8ap\\\\ npu~~a=\cfrac{2}{7};~p=-3,5\\\\8ap=8\cdot\cfrac{2}{7}\cdot(-3,5)=8\cdot\cfrac{2}{7}\cdot\bigg(-\cfrac{7}{2}\bigg)=8\cdot(-1)=-8](https://tex.z-dn.net/?f=%5Ctt+%282a%2Bp%29%5E2-%282a-p%29%5E2%3D%282a%2Bp-%282a-p%29%29%282a%2Bp%2B2a-p%29%3D%5C%5C%5C%5C%3D%282a%2Bp-2a%2Bp%29%284a%29%3D2p%5Ccdot4a%3D8ap%5C%5C%5C%5C+npu~~a%3D%5Ccfrac%7B2%7D%7B7%7D%3B~p%3D-3%2C5%5C%5C%5C%5C8ap%3D8%5Ccdot%5Ccfrac%7B2%7D%7B7%7D%5Ccdot%28-3%2C5%29%3D8%5Ccdot%5Ccfrac%7B2%7D%7B7%7D%5Ccdot%5Cbigg%28-%5Ccfrac%7B7%7D%7B2%7D%5Cbigg%29%3D8%5Ccdot%28-1%29%3D-8)
(6а-2)^2=36а^2-24а+4
(5b+6)^2=25b^2+60b+36
(4+2a)^3=64+96a+32a^2+8a^3
(2a-1)^3=8a^3-12a^2+6a-1