1A:

a: \(x^3+2x=x\left(x^2+2\right)\)

b: \(3x-6y=3\left(x-2y\right)\)

c: \(5\left(x+3y\right)-15x\left(x+3y\right)\)

\(=5\left(x+3y\right)\left(1-3x\right)\)

d: \(3\left(x-y\right)-5x\left(y-x\right)\)

\(=3\left(x-y\right)+5x\left(x-y\right)\)

\(=\left(x-y\right)\left(5x+3\right)\)

1A. a. x(x²+2) 

b. 3(x-2y)

c. 5(x+3y)(1-3x) 

d. (x-y) (3-5x)

1B. a. 2x(2x-3)

b.xy(x²-2xy+5)

c. 2x(x+1)(x+2)

d. 2x(y-1)+2y(y-1)=2(y-1)(x-y)

a, = 3x ( x - 2 )

b, = ( x² + 4x + 4 ) - 25y²

= ( x + 2 )² - 25y²

= ( x + 2 - 5y ) ( x + 2 + 5y )

c, 2x² - 5x + 3           

= 2x² - 6x + x + 3

= 2x ( x - 3 ) + ( x - 3 )

= ( x - 3 ) ( 2x + 1 )

\(a,3x^2-6x=3x.\left(x-2\right)\\ b,x^2+4x-25y^2+4=\left(x^2+4x+4\right)-25y^2\\ =\left(x+2\right)^2-\left(5y\right)^2\\ =\left(x-5y+2\right).\left(x+5y+2\right)\\ c,2x^2-5x-3\\ =2x^2-6x+x-3\\ =2x.\left(x-3\right)+\left(x-3\right)\\ =\left(2x+1\right).\left(x-3\right)\)

\(a,=2xy\left(2y-x\right)\\ b,=x^2\left(x-4\right)+5\left(x-4\right)=\left(x^2+5\right)\left(x-4\right)\\ c,=\left(x-y\right)\left(x^2-25\right)=\left(x-y\right)\left(x-5\right)\left(x+5\right)\)

a: \(=\dfrac{2}{5}\left(xy-x-y^2+1\right)\)

\(=\dfrac{2}{5}\left[x\left(y-1\right)-\left(y-1\right)\left(y+1\right)\right]\)

\(=\dfrac{2}{5}\left(y-1\right)\left(x-y-1\right)\)

b: \(=x\left(x^2+2xy+y^2-9\right)\)

\(=x\left(x+y-3\right)\left(x+y+3\right)\)

a) $=\frac{2}{5}\left(xy-x-y^2+1\right)$

$=\frac{2}{5}\left[x\left(y-1\right)-\left(y-1\right)\left(y+1\right)\right]$

$=\frac{2}{5}\left(y-1\right)\left(x-y-1\right)$

b) $=x\left(x^2+2xy+y^2-9\right)$

$=x\left(x+y-3\right)\left(x+y+3\right)$

\(a,=5x\left(4x-1\right)\\ b,=y^2-\left(x-1\right)^2=\left(y-x+1\right)\left(y+x-1\right)\\ c,=6x^2+3x-4x-2=3x\left(x+2\right)-2\left(x+2\right)=\left(3x-2\right)\left(x+2\right)\)

a: =5(2x+3y)

d: =(x+1-y)(x+1+y)

a)  \(x^4+2x^3+5x^2+4x-12\)

\(=x^4+x^3+6x^2+x^3+x^2+6x-2x^2-2x-12\)

\(=x^2\left(x^2+x+6\right)+x\left(x^2+x+6\right)-2\left(x^2+x+6\right)\)

\(=\left(x^2+x+6\right)\left(x^2+x-2\right)\)

\(=\left(x^2+x+6\right)\left(x-1\right)\left(x+2\right)\)

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

b) \(4x^2 -8x+3 \\= (2x^2)-2.2x .2 + 2^2 -1 \\=(2x-2)^2-1^2\\=(2x-2+1)(2x-2-1)\\= (2x-1)(2x-3)\)

\(5x^2+10xy=5x\left(x+2y\right)\)

\(x^2+xy-3x-3y=x\left(x+y\right)-3\left(x+y\right)=\left(x-3\right)\left(x+y\right)\)

\(x^2+2x+1-y^2=\left(x+1\right)^2-y^2=\left(x+1-y\right)\left(x+1+y\right)\)

\(x^2-7x+6=x^2-x-6x+6=x\left(x-1\right)-6\left(x-1\right)=\left(x-1\right)\left(x-6\right)\)

c: \(x^2-10x+21=\left(x-3\right)\left(x-7\right)\)

a: \(x^2y+xy^3-xy-y^3\)

\(=xy\left(x-1\right)+y^3\left(x-1\right)\)

\(=y\left(x-1\right)\left(x+y^2\right)\)