15<r<16
225<r²<256
15<h<16
225*15<r²h<256*16
3375<r²h<4096
3,14<π<3,15
3375*3,14<πr²h<4096*3,15
10597,5<πr²h<12902,4
{x+y=-1 x=-1-y
{x2+y2=1
(-1-y)^2 +y^2-1=0
1+2y+y^2+y^2-1=0
2y(y+1)=0
2y=0 y+1=0
y=0 y=-1
x1=-1-0=-1
x2=-1-(-1)=-1+1=0
ж:(-1;0) (0;-1)
Найдем х и у методом сложения, сложив обе части системы:
![\left \{ {{3x-2y=7} \atop {2x+2y=8}} \right. \\ 3x+2x=7+8\\ 5x=15\\ x=3\\ \left \{ {{x=3} \atop {2x+2y=8}} \right. \\ \left \{ {{x=3} \atop {2*3+2y=8}} \right. \\ \left \{ {{x=3} \atop {2y=2}} \right. \\ \left \{ {{x=3} \atop {y=1}} \right. \\ OTBET:(3;1).](https://tex.z-dn.net/?f=+%5Cleft+%5C%7B+%7B%7B3x-2y%3D7%7D+%5Catop+%7B2x%2B2y%3D8%7D%7D+%5Cright.+%5C%5C+3x%2B2x%3D7%2B8%5C%5C+5x%3D15%5C%5C+x%3D3%5C%5C++%5Cleft+%5C%7B+%7B%7Bx%3D3%7D+%5Catop+%7B2x%2B2y%3D8%7D%7D+%5Cright.++%5C%5C++%5Cleft+%5C%7B+%7B%7Bx%3D3%7D+%5Catop+%7B2%2A3%2B2y%3D8%7D%7D+%5Cright.++%5C%5C++%5Cleft+%5C%7B+%7B%7Bx%3D3%7D+%5Catop+%7B2y%3D2%7D%7D+%5Cright.++%5C%5C++%5Cleft+%5C%7B+%7B%7Bx%3D3%7D+%5Catop+%7By%3D1%7D%7D+%5Cright.++%5C%5C+OTBET%3A%283%3B1%29.)
1) -5x^2+20=14x-4
-5x^2+20-14x+4=0
5x^2-20+14x-4=0
5x²+14x-25=0
D=14²-4*5*(-25)=196-500≠-304