帮忙做一下，因式分解,忘了。。。做出有重赏 要快！！

Question

3x²+5xy-2y²+x+9y-4 2x²+xy-y²-4x+5y-6 x²-2√2 x-3 8a³-b³
x²+x-(a²-a) 3x²+4xy-y² x²-5x+3
(a+2b-c)²=a²+4b²+c²+( )

Answer 1

3x^2+5xy-2y^2+x+9y-4
=(x+2y)(3x-y)+x+9y-4
=(x+2y)(3x-y)+4(x+2y)-(3x-y)-4
=(x+2y-1)(3x-y+4)

2x^2+xy-y^2-4x+5y-6
=(2x-y)(x+y)-4x+5y-6
=(2x-y)(x+y)+(2x+2y)-4x-2x+5y-2y-6
=(2x-y)(x+y)+2(x+y)-6x+3y-6
=(x+y)(2x-y+2)-3(2x-y+2)
=(2x-y+2)(x+y-3)

x^2-2√2*x-3
=x^2-2√2*x+2-2-3
=(x-√2)^2-5
=(x-√2-√5)(x-√2+√5)

8a^3-b^3
=(2a-b)(4a^2+2ab+b^2)

x^2+x-(a^2-a)
=(x^2-a^2)+x+a
=(x+a)(x-a)+(x+a)
=(x+a)(x-a+1)

3x^2+4xy-y^2
= 3(x^2+ xy*4/3 - y^2*1/3)
= 3[(x^2+ 2*2/3 *xy +4/9y^2) - y^2/3- 4/9y^2]
= 3[(x+2/3y)^2 - 7/9 y^2]
=3(x+2/3y +√7/3y)(x+2/3y - √7/3y)
= 3[x+(2+√7)/3y][x+(2-√7)/3y]

x^2-5x+3
=x^2-5x+25/4-25/4+3
=(x-5/2)^2-13/4
=(x-5/2-√13/2)(x-5/2+√13/2)

(a+2b-c)²=a²+4b²+c²+( 4ab-2ac-4bc )