$\left(x\ -\ 4y\right)\left(x+4y\right)$  

 $x^2\left(x\ -\ 4y\right)\left(x+4y\right)$  

 $\left(x^2-4y\right)\left(x^2+4y\right)$  

 $x^2y\left(x^2-16y\right)$  

(x - 5)(x - 4)

(x - 5)(x + 4)

(x + 5)(x + 4)

(x + 5)(x - 4)

 $\left(x^2+6\right)\left(x^2+3\right)$  

 $x^2\left(x+3\right)\left(x+6\right)$  

 $\left(x^2+2\right)\left(x^2+9\right)$  

 $\left(x^2+2\right)\left(x^2+11\right)$  

(x + 20)(x - 2)

(x + 8)(x - 5)

(x + 10)(x - 4)

(x - 5)(x - 8)

 $\left(2x\ +\ 3\right)\left(4x^2+3x\ +6\right)$  

 $\left(2x+3\right)\left(2x^2-3x\ +\ 9\right)$  

 $\left(2x\ -\ 3\right)\left(2x^2+6x+9\right)$  

 $\left(2x\ +3\right)\left(4x^2-6x\ +\ 9\right)$  

(2x - 1)(x - 6)

(2x - 1)(x + 6)

(2x + 1)(x - 6)

(2x + 1)(x + 6)

 $\left(2x^2+5\right)\left(x+6\right)$  

 $2x\left(x^2+8x+15\right)$  

2x(x + 5)(x + 3)

2x(x - 3)(x  - 10)

(a - 5)(x - b)

(a - 5)(x + b)

(a+ 5)(x + b)

(a - 5)(x - b)

(6x + 5)(x +1)

(3x + 5)(2x + 1)

(3x + 1)(2x + 5)

(6x +1)(x + 5)