Помогите!!! Срочно!!​

2.

.......=8a³ - 1

при  а= -1/2

8*(-1/2)³ - 1= - 8*1/8 - 1= - 1 - 1= - 2

3.

1)   ......=(x-y)(x+y)+(x-y)=(x-y)(x+y+1)

2)   .....=(2x-y)² - 9=(2x-y-3)(2x-y+3)

3)   ....=ac⁴- ac² - c⁴+c²=ac²(c² - 1)-c²(c² - 1)=(ac² - c²)(c²-1)=c²(a-1)(c-1)(c+1)

4)   .....=4 - (m² - 2mn+n²)=4 - (m-n)²=(2-m+n)(2+m-n)

4.

6х³-24х=0

х³ - 4х=0

х(х²-4)=0

х1=0.

(х-2)(х+2)=0

х-2=0

х2=2.

х+2=0

х3= - 2

.

.

25х³-10х²+х=0

х(25х² - 10х+1)=0

х1=0.

25х²-10х+1=0

D/4=5²-25=0

х=5/25=1/5

х2=0,2.

.

.

х³-4х²-9х+36=0

х(х²-9)-4(х²-9)=0

(х-4)(х²-9)=0

(х-4)(х-3)(х+3)=0

х-4=0

х1=4.

х-3=0

х2=3.

х+3=0

х3= - 3