Difference of Squares Review

What is ALWAYS the first step when factoring?

• Look for the GCF

• Write a, b, and c

• Difference of squares

• Group

Factor 4x²-9

• (4x-9)(4x+9)

• (2x-3)(2x+3)

• 2x-3

• (2x-4.5)(2x+4.5)

Fully Factor the Following
25x²-81

• (5x-9)²
• (5x+9)(5x-9)
• 25(x-9)²
• (9x+5)(9x-5)

3x² - 75

• 3( x + 5 ) ( x - 5 ) 
• Prime
• ( x + 5 ) ( x - 5 ) 
• 3( x - 5 ) ( x - 5 ) 

r⁴ - q⁴

• (r² + q²) (r² - q²)
• (r² - q²) (r² - q²)
• (r + q) (r - q)
• Can't factor using Diff. of Squares

9n² + 1

• (3n + 1) (3n - 1)
• (3n - 1) (3n - 1)
• (n + 3) (n - 3)
• Can't factor using Diff. of Squares

r² - 9t²

• (r + 3t) (r - 3t)
• (r - 3t) (r - 3t)
• (3r + t) (3r - t)
• Can't factor using Diff. of Squares

36x² - 64

• (6x - 8)(6x + 8)
• 4(3x - 4)(3x + 4)
• Not Factorable
• (9x - 16)(9x + 16)

Which of these can factor using difference of two squares?

• 144x² - 49y²

• x² + 4x - 12

• 100x² + 20x + 1

• 14x - 16

Which one is false about the difference of two squares?

• We can factor because there is addition sign.

• We can factor because there is a perfect squared number (Example: x², 25, 49)

• Formula: a² - b² = (a + b) (a - b)

• We can factor because there is minus sign.