September 17, 2008

Well for today, Dr. Eviatar helped us with some questions we didnt quite understand on Exercise 10 - Factoring Difference of Squares.

She did some questions with us and here they are:

3. a.
a² - b²
(a - b) (a + b)
81 - (x + 7)²
9² - (x + 7)²
↑
a² - b²
[9 - (x + 7)] [9 + (x + 7)]
[9 - x - 7] [9 + x + 7]
(2 - x) (16 + x)

b.
(x - 1)² - (x + 1)²
(x - 1) (x - 1) - (x +1)(x + 1)
(x² - 2x + 1) - (x² + 2 + 1)
x² - 2x + 1 - x² - 2x - 1
-2x - 2x
= -4x

4. a.
x^8 - y¹²
(x^4)² - (y^6)² =
(x^4 - y^6) (x^4 + y^6) =
(x² - y³) (x² + y³) (x^4 + y^6)
x² - 16
x² - 0x - 16
(x - 4) (x + 4)

5. a.
4m² - 25y^4
↑
(2m)² - (5y²)²
121x² - 196y²
(11x)² - (14y)

Before classes ended, she told us to study the stuff we learned to be prepared for our Pre-Test tomorrow.
Now get studying for the REAL TEST on Friday to be ready.
- Good Luck!

& the next scribe will be : Lia! :)