1.(x^2 + 4x – 12)(x^2 – 15x +56)= 0
x^2 + 4x – 12 = 0
D=16+48=64
X1= (-4+8)/2=2
X2= (-4-8)/2=-6
x^2 – 15x +56 = 0
D=225-224=1
X1= (15+1)/2=8
X2= (15-1)/2=7
Ответ: -6; 2; 7; 8.
2. √x (x^2 + 6x - 55) (-x^2 + 11x - 28) = 0
ОДЗ
x>=0
√x=0
X=0
x^2 + 6x – 55 = 0
D=36+220=256
X1= (-6+16)/2=5
X2= (-6-16)/2=-11(посторонний)
-x^2 + 11x – 28 = 0
x^2 - 11x + 28 = 0
D=121-112=9
X1= (11+3)/2=7
X2= (11-3)/2=4
Ответ: 0; 4; 5; 7.
3. √(6-x) (x^2 + 10x + 9) (x^2 – 5x + 4) = 0
ОДЗ
6-х>=0
X<=6<br>
√(6-x)=0
6-x=0
X=6
x^2 + 10x + 9 = 0
D=100-36=64
X1= (-10+8)/2=-1
X2= (-10-8)/2=-9
x^2 – 5x + 4 = 0
D=25-16=9
X1= (5+3)/2=4
X2= (5-3)/2=1
Ответ: -9; -1; 1; 4; 6.