Tgx = 3
sinx/cosx = 3
sinx = 3cosx
Подставляем вместо синуса 3cosx:
(9cosx + cosx)/(3cosx - 4cosx) = 10cosx/(-cosx) = -10.
Ответ: -10.
-2х+6у=-16
2х-у=6
5у=10
у=2
2х=6+2
2х=8
х=4
5x+7y=3
2x-y =4 14x-7y=28
5x+7y+14x-7y=3+28
19x=31 x=31/19
y=2x-4=2*31/19-4 =62/19-4=-14/19
x-2y=4
x+y=5
x-2y-x-y= -1 3y=1 y=1/3
x-2/3=4 x= 4 2/3
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