3,6а+2,7b-1,2a+5,4b=2,4а+8,1b=2,4-40,5=-38,1
![\left \{ {{b1+b3=30} \atop {b2+b4=90}} \right.](https://tex.z-dn.net/?f=+%5Cleft+%5C%7B+%7B%7Bb1%2Bb3%3D30%7D+%5Catop+%7Bb2%2Bb4%3D90%7D%7D+%5Cright.+)
⇒
![\left \{ {{b1+b1q ^{2} =30} \atop {b1q+b1q^3=90}} \right.](https://tex.z-dn.net/?f=+%5Cleft+%5C%7B+%7B%7Bb1%2Bb1q+%5E%7B2%7D+%3D30%7D+%5Catop+%7Bb1q%2Bb1q%5E3%3D90%7D%7D+%5Cright.+)
![\left \{ {{b1(1+q^2)=30} \atop {b1q(1+q^2)=90}} \right.](https://tex.z-dn.net/?f=+%5Cleft+%5C%7B+%7B%7Bb1%281%2Bq%5E2%29%3D30%7D+%5Catop+%7Bb1q%281%2Bq%5E2%29%3D90%7D%7D+%5Cright.+)
1+q²=30/b₁; ⇒b1·q·30/b1=90; ⇒q=9/30=3;
b1=30/(1+q²)=30/(1+9)=30/10=3;
А) 6х-5х=10+4
Х=14
Б) х-4х=-9-1,5
-3х=-10,5
Х=-10,5:(-3)х=3,5
В)2,9х-3,6х=-6.3
-0,7х=-6.3
Х=-6.3:(-0,7)
Х=9
Г)-3х-27=4х+8
-3х-4х=8+27
-7х=35
Х=35:(-7)
Х=-5
Sqrt((x2-x1)^2 + (y2-y1)^2) = > MN= sqrt((-2-1)^2+(3-(-2))^2) = sqrt(34).
Также и для NK и KM. NK=sqrt(29), KM=sqrt(13). И периметр будет 14.82ед