<span>(x+6)(x+3) <0
х</span>₁= -6 , х₂=-3
х∈ ( -6; -3)
Ответ: <span>х∈ ( -6; -3)</span>
4х = 18 - 7y
4x = 6 - 5y
18 - 7y = 6 - 5y
7y - 5y = 18 - 6
2y = 12
y = 6
4x = 6 - 5•6
4x = 6 - 30
X = - 24 : 4
X = - 6
Ответ ( - 6 ; 6 )
{х+у=2
{ху/2=(х+у)/2
{х=2-у
{ху=х+у
(2-у)×у=2-у+у
2у^2=2
у^2=1
у1=1
у2=-1
х1=2-1=1
х2=2-(-1)=3
(1;1)(3;-1)
<span>a10=a1+9d=17
a5=a+4d
a10-a5=a+9d-(a+4d)=5d=17-4=13
5d=13 => d=13/5
a5=a+4*13/5=4
a+4*13/5=4 => a=-32/5
S10=1/2(a1+a10)*15=1/2(2a+14d)*15=1/2(-2*32/5+14*13/5)*15=177</span>