1)
(x+2)(2x-1)=2x^2-x+4x-2=2x^2+3x-2
(2-y)(y^2+3) =2y^2+6-y^3-3y
(а+4)(1-а)+а ^2=a-a^2+4-4a=-a^2+4-3 a
(b+2)(b^2-b+2)=b^3-b^2+2b+2b^2-2b^2+4=b^3-b^2+4
2) ab+2b+ac+2c=(a+c)^2
3) 2х(2-3х)(3х+2)=8х-18х^3.
2x(6x+4-9x^2-6x)= 8x-18x^3
2x(4-9x^2)=8x-18x^3
8x-18x^2=8x-18x^3
-18x^2+18x^3=8x-8x
-18x^2+18x^3=0
x^2(-18+18x)=0
x^2=0 -18+18x=0
18 x=18
x=1
![\left \{ {{x\ \textgreater \ -11} \atop {x \leq 2}} \right.](https://tex.z-dn.net/?f=+%5Cleft+%5C%7B+%7B%7Bx%5C+%5Ctextgreater+%5C+-11%7D+%5Catop+%7Bx+%5Cleq+2%7D%7D+%5Cright.+)
Значения х больше -11, но меньше или равно 2, поэтому ответ:
х∈(-11;2].
X² - 3x + 2- x² = 2
- 3x = 2 - 2
- 3x=0
x = 0
1) a/(a -b) - (a -b)/(a +b) =(a(a+b) -(a-b)(a-b)) /(a-b)(a+b) =(a²+ab -(a²-2ab+b²)) /(a-b)(a+b) =(a²+ab-a²+2ab-b²) /(a-b)(a+b) =(3ab -b²) /(a²-b²)
2) =2(x-y)/y *3y²/(x-y)(x+y) =2(x -y)*3y² /y*(x -y)(x +y) =6y/(x+y)
3) (3v5)² /15 =9*5 /15 =9/3 =3
значок v обозначает корень