4 1/2 + 3 1/5 = 9/2 + 16/5 =(9 × 5 16 × 2)/10 = 45/10 + 32/10 = 77/10 = 7 7/10
77/10 ÷ 113 = 77/10 × 1/113 = 77/1130
ответ 77/1130
<span>(0,018+0,982)/(8*0,5-0,8)=0,3125
0,018+0,982=1
8*0,5=4
4-0,8=3,2
1/3,2=0,3125
</span><span>
</span>
2x-ky=5
<span>3x+2y=6
</span>..............
6x-3kx=15
6x+4y=12
..............
4y+3kx=-3
................
k=(-3-4y)/3y
при k = 0, система не имеет решений
![\left \{ {{2y+3x=0 } \atop {6(x-7)+8y=0}} \right. \\ \left \{ {{3x+2y=0} \atop {6x-42+8y=0}} \right. \\ \left \{ {{3x+2y=0} |*(-2)\atop {6x+8y=42}} \right. \\ \left \{ {{-6x-4y=0} \atop {6x+8y=42}} \right. \\](https://tex.z-dn.net/?f=+%5Cleft+%5C%7B+%7B%7B2y%2B3x%3D0+%7D+%5Catop+%7B6%28x-7%29%2B8y%3D0%7D%7D+%5Cright.+%5C%5C+%5Cleft+%5C%7B+%7B%7B3x%2B2y%3D0%7D+%5Catop+%7B6x-42%2B8y%3D0%7D%7D+%5Cright.+%5C%5C+%5Cleft+%5C%7B+%7B%7B3x%2B2y%3D0%7D+%7C%2A%28-2%29%5Catop+%7B6x%2B8y%3D42%7D%7D+%5Cright.+%5C%5C+%5Cleft+%5C%7B+%7B%7B-6x-4y%3D0%7D+%5Catop+%7B6x%2B8y%3D42%7D%7D+%5Cright.+%5C%5C+)
Складываем уравнения почленно:
![4y=42 \\ y=10,5 \\](https://tex.z-dn.net/?f=4y%3D42+%5C%5C+y%3D10%2C5+%5C%5C+)
Подставляем y в первое уравнение:
![2y+3x=0 \\ 2*10,5+3x=0 \\ 21+3x=0 \\ 3x=-21 \\ x=-7 \\ ](https://tex.z-dn.net/?f=2y%2B3x%3D0+%5C%5C+%0A2%2A10%2C5%2B3x%3D0+%5C%5C+%0A21%2B3x%3D0+%5C%5C+%0A3x%3D-21+%5C%5C+%0Ax%3D-7+%5C%5C+%0A)
Ответ: (-7 ; 10,5).
100 м=10000 см на плане как 1 см.
формула s=a*b, но здесь s=a*b/10^8
s=10000*1200/10^8=0.12 см2