6y + 3x = 5
5x + 3y = - 1
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- 6y - 3x = - 5
10x + 6y = - 2
7x = - 7
x = - 1
- 5 + 3y = - 1
3y = 4
y = 1 1/3
Ответ ( - 1 ; 1 1/3 )
Cos(-4x)cos(-x)+sin(-4x)sin(-x)=1
cos4xcosx+sin4xsinx=1
(cos(4x-x)+cos(4x+x))/2 + (cos(4x-x)-cos(4x+x))/2 = 1
(cos3x+cos5x+cos3x-cos5x)/2 = 1
(2cos3x)/2 = 1
cos3x=1
3x=2πn, n∈Z
x=(2πn)/3, n∈Z
M²/mn=m/n
4ab/4bc=a/c
1)1/3a²b-дробь
2)x-y/x=(x²-y)/x - дробь
3)c+2/9 - дробь,
4)p²-p-19 - целое