Mar. 10/17
* = (x)(3x) + (x)(2) - (1)(3x) - (1)(2) * = (d)(d) + (d)(2) - (6)(d) - (6)(2)
= 3x2 + 2x - 3x - 2
= d2 + 2d - 6d - 12
= 3x - x - 2
= d2 - 4d - 12
2
* this line is not necessary
≠ (x)2 + (3)2
= 6a2 - 21ab +8ab -28b2
= 6a2 - 13ab -28b2
= (x + 3)(x + 3)
= x2 + 3x + 3x + 9
= x2 + 6x + 9
= (2x - 5)(2x - 5)
= 4x2 - 10x - 10x + 25
= 4x2 - 20x + 25
= 5(2x2 - 6x + x - 3)
= 5(2x2 - 5x - 3)
= 10x2 - 25x - 15
= 6x(2x + 1)(2x + 1)
= 6x(4x2 + 2x + 2x + 1)
= 6x(4x2 + 4x + 1)
= 2(x + 2)(x + 2) - 3x(2x - 4)
= 2(x2 + 2x + 2x + 4) - 6x2 + 12x
= 2(x2 + 4x + 4) - 6x2 + 12x
= 2x2 + 8x + 8 - 6x2 + 12x
= 24x3 + 24x2 + 6x
= -4x2 + 20x + 8
The word FOIL helps us to remember how to expand two binomials.
First
Outer
Inner
Last
We can also use a table to help expand binomials.
x -3
x
+
5
-
= x2 - 3x + 5x - 15
= x2 + 2x - 15
OR
Algebra Tiles
+1
-1
= x2 + 2x - 15
1