DOTS and GCF

x² - 9

• (x + 3)²

• (x + 3) (x - 3)

• (x - 3)²

• x + 3(x - 3)

x² - 16

• (x + 4) (x - 4)

• (x + 8) (x - 2)

• (x + 4)²

• x + 4(x - 4)

Which of the following is NOT a perfect square?

• 1

• 4

• 100

• 8

We can't factor 49x² + 4y² using the difference of two squares.

Why?

• Because 4 is not a perfect cubed number.

• Because 4 is not a perfect squared number.

• Because 49 is not a perfect squared number.

• Because we can't factor using difference of two squares if it is addition sign.

Factor 4x²-9

• (4x-9)(4x+9)

• (2x-3)(2x+3)

• 2x-3

• (2x-4.5)(2x+4.5)

49x² - 144y²

• (7x + 16y) (7x - 16y)

• (7x + 12y)²

• (12x + 7y) (12x - 7y)

• (7x + 12y) (7x - 12y)

What is the GCF of 18k and 15k³?

• 3k²
• 3k³
• 3k
• 5k

 $x^2-25$  

•  $\left(x-5\right)\left(x-5\right)$  

•  $\left(x^2-5\right)\left(x^2+5\right)$  

•  $\left(x-5\right)\left(x+5\right)$  

•  $\left(x+25\right)\left(x-25\right)$  

Factor completely.

49x² + 16

• ( 7x + 4 ) ( 7x - 4 )

• ( 7x + 4 ) ( 7x + 4 )

• ( 7x - 4 ) ²

• does not factor (SUM of squares)

 $9x^2-16$  

•  $\left(9x-4\right)\left(9x+4\right)$  

•  $\left(3x-8\right)\left(3x+8\right)$  

•  $\left(3x-4\right)\left(3x+4\right)$  

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