Ch3 Revision

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)

4x² - 25

• (2x + 5) (2x - 5)

• (2x - 5)²

• (2x + 5)²

• 2x + 5(2x - 5)

25x² - 36y²

• 5x + 6y(5x - 6y)

• (5x + 6y) (5x - 6y)

• (5x + 6y)²

• (5x - 6y)²

4x²y² - 1

• (2 + xy) (2 - xy)

• (2x + y) (2x - y)

• (2xy + 1) (2xy - 1)

• (2y + x) (2y - x)

64x² - 81y²

• (8x + 7y) (8x - 7y)

• (8x + 9y) (8x - 9y)

• (6x + 7y) (6x - 7y)

• (6x + 9y) (6x - 9y)

4x² - 16

• 4(2x + 4) (x - 2)

• 4(4x + 2) (x - 2)

• (2x + 4) (2x - 4)

• 4(x + 2) (x - 2)

49x² - 144y²

• (7x + 16y) (7x - 16y)

• (7x + 12y)²

• (12x + 7y) (12x - 7y)

• (7x + 12y) (7x - 12y)

We can't factor using difference of two square this

25x² - 51y². Why?

• Because 51 is not a perfect cubed number.

• Because 51 is not a perfect squared number.

• Because 25 is not a perfect squared number.

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

What is ALWAYS the first step when factoring?

• Look for the common factors

• Write a, b, and c

• Difference of squares

• Use the cross-method