Получаются подобные треугольники.
Составим отношение:
4--2
Х--1,5
Отсюда:
4*1,5/2=3метра
Ответ. на 3 метра опустится длинное плечо
6-18с+21b-35c+44-8b=-53c+13b+50
3х-4у=-5
+
6х+4у=-1
9х=-6
х=-9/6
х=-1.5
-4у=-5-3*(-1.5)
-4у=-0.5
у=8
как я понимаю тут написано
x^2-3x-10=0
D=9-4*(-10)=49
x1=3+7/2=10/2=5
x2=3-7/2=-4/2=-2
ответ:x1=5;x2=2
или если там вместо (-),плюс,то решается так x^2+3x-10x=0
D=9-4*(-10)=49
x1=-3+7/2=4/2=2
x2=-3-7/2=-10/2=-5
Ответ:x1=2; x2=-5
A)D=b^2-4ac=16-(-84)=100 k=
![\sqrt{100}](https://tex.z-dn.net/?f=+%5Csqrt%7B100%7D)
=10
x1=(-k+
![\sqrt{k^2-ac}](https://tex.z-dn.net/?f=+%5Csqrt%7Bk%5E2-ac%7D+)
)/a=(-10+
![\sqrt{100+21}](https://tex.z-dn.net/?f=+%5Csqrt%7B100%2B21%7D+)
)/1=-10+
![\sqrt{121}](https://tex.z-dn.net/?f=+%5Csqrt%7B121%7D+)
=-10+11=1
x2=(-k
![\sqrt{k^2-ac}](https://tex.z-dn.net/?f=+%5Csqrt%7Bk%5E2-ac%7D+)
)/a=(-10-
![\sqrt{100+21}](https://tex.z-dn.net/?f=+%5Csqrt%7B100%2B21%7D+)
)/1=-10-
![\sqrt{121}](https://tex.z-dn.net/?f=+%5Csqrt%7B121%7D+)
=-10-11=-21
b)D=16+84=100 k=10
x1=(-10+
![\sqrt{100+21}](https://tex.z-dn.net/?f=+%5Csqrt%7B100%2B21%7D+)
)/7=(-10
![\sqrt{121}](https://tex.z-dn.net/?f=+%5Csqrt%7B121%7D+)
)/7=(-10-11)/7=-3
x2=(-10-
![\sqrt{100+21}](https://tex.z-dn.net/?f=+%5Csqrt%7B100%2B21%7D+)
)/7=(-10-
![\sqrt{121}](https://tex.z-dn.net/?f=+%5Csqrt%7B121%7D+)
)/7=(-10+11)/7=1/7
c)D=4+8=12 k=
![\sqrt{12}](https://tex.z-dn.net/?f=+%5Csqrt%7B12%7D+)
x1=
![(-\sqrt{12} - \sqrt{ \sqrt{12} +2} )/2=(-2 \sqrt{3} - \sqrt{2 \sqrt{3} +2} )/2=(-2 \sqrt{3} -](https://tex.z-dn.net/?f=+%28-%5Csqrt%7B12%7D+-+%5Csqrt%7B+%5Csqrt%7B12%7D+%2B2%7D+%29%2F2%3D%28-2+%5Csqrt%7B3%7D+-+%5Csqrt%7B2+%5Csqrt%7B3%7D+%2B2%7D+%29%2F2%3D%28-2+%5Csqrt%7B3%7D+-+)
![\sqrt{2( \sqrt{3}+1 } ))/2](https://tex.z-dn.net/?f=%5Csqrt%7B2%28+%5Csqrt%7B3%7D%2B1+%7D+%29%29%2F2)
x2=
![(-\sqrt{12} +\sqrt{ \sqrt{12} +2} )/2=(-2 \sqrt{3} +\sqrt{2 \sqrt{3} +2} )/2=[tex](-2 \sqrt{3} - \sqrt{2( \sqrt{3}+1 } ))/2](https://tex.z-dn.net/?f=%28-%5Csqrt%7B12%7D+%2B%5Csqrt%7B+%5Csqrt%7B12%7D+%2B2%7D+%29%2F2%3D%28-2+%5Csqrt%7B3%7D+%2B%5Csqrt%7B2+%5Csqrt%7B3%7D+%2B2%7D+%29%2F2%3D%5Btex%5D%28-2+%5Csqrt%7B3%7D+-+%5Csqrt%7B2%28+%5Csqrt%7B3%7D%2B1+%7D+%29%29%2F2)
/