(a - 2)x² - 2(a + 1)x + 3a + 3 = 0
D = 4(a + 1)² - 4(a - 2)(3a + 3) = 4a² + 8a + 4 - 4(3a² - 3a - 6) = 4a² + 8a + 4 - 12a² + 12a + 24 = -8a² + 20a + 28 = 4(7 + 5a - 2a²)
x ∈ ∅ ⇒ D < 0
7 + 5a - 2a² < 0
2a² - 5a - 7 > 0
D = 25 + 56 = 81 = 9²
a1 = 14/4 = 3,5
a2 = -1
2(x - 3,5)(x + 1) > 0
Відповідь :a ∈ (-∞; -1)∪(3,5 ; +∞)
<span>6х^2-2х+3=х^2-11х-1
</span>6х^2-х^2-2х+11х=-1-3
5х^2+9х=-4
5х(х+9)=-4
5х=-4 х=?
х=-0,8
A)xˇ2+8xy+16yˇ2=25, (x+4y)ˇ2=25
4yˇ2+xy=5, y(x+4y)=5, (x+4y)=5/y
(5/y)ˇ2=25, 25/yˇ2 =25,25=25.yˇ2, yˇ2=1
y1=1, y2=-1
1)y1=1, 4.1ˇ2 +x.1=5,4+x=5, x1=1
/x,y/ = /1,1/
2)y1=-1, 4.(-1)ˇ2+x(-1)=5,4-x=5, x2=-1
/x,y/=/-1,-1/