3x+12=2x-1
3x-2x=-1-12
x=-13
6x-2(4x-1)=7
6x-8x+2=7
6x-8x=7-2
-2x=5
x=5/(-2)
x=-2.5
Начало координат - O
Гомотетия с коэффициентом k:
![\stackrel{\longrightarrow}{OA_1}=k*\stackrel{\longrightarrow}{OA}\\\stackrel{\longrightarrow}{OA}=\{2;-8\},\,\stackrel{\longrightarrow}{OA_1}=\{-1;4\}\Rightarrow\\\\k={-1\over2}={4\over-8}=-{1\over2}](https://tex.z-dn.net/?f=%5Cstackrel%7B%5Clongrightarrow%7D%7BOA_1%7D%3Dk%2A%5Cstackrel%7B%5Clongrightarrow%7D%7BOA%7D%5C%5C%5Cstackrel%7B%5Clongrightarrow%7D%7BOA%7D%3D%5C%7B2%3B-8%5C%7D%2C%5C%2C%5Cstackrel%7B%5Clongrightarrow%7D%7BOA_1%7D%3D%5C%7B-1%3B4%5C%7D%5CRightarrow%5C%5C%5C%5Ck%3D%7B-1%5Cover2%7D%3D%7B4%5Cover-8%7D%3D-%7B1%5Cover2%7D)
2с=3с-1
с = 1
а = 3
<span>Ответ: 9+1\1=10</span>
D² + 0.2d + 0.01 - 0.25d² = 0
0.75 d² + 0.2d + 0.01 = 0
75d² + 20d + 1 = 0
D = 400 - 4·75 = 100
√D = 10
d1 = (-20 -10) : 150 = - 0.2
d2 = (-20 + 10) : 150 = -1/15