Y=2.5x-10
y=5-3x
тогда
2.5x-10=5-3x
5.5x=15
x=30/11
Y = a*x^2
12 = a*( - 2)^2
4a = 12
a = 3
<span>sinx-sin3x/cosx-cos3x*(1-cos4x)=-2sinxcos2x/2</span>sinxsin2x *2sin²2x=2cos2xsin2x=
=-sin4x
-sin4x=-sin4x
Х - y = 6
5x - 2y = - 3
- 2x + 2y = - 12
5x - 2x - 2y + 2y = - 3 - 12
3x = - 15
X = - 5
-5 - y = 6
Y = - 11
Ответ ( - 5 ; - 11 )
4.5х+3х=93
3х=93-4.5
3х=88.5
х=29.5