October 04, 2016
Expand and Simplify
(x­5)2 ­ (3x+5)
2
Simple Trinomials
­ has three terms with the form...
ax2 + bx + c
­ a simple trinomial has an "a" value of 1.
­ we use a method of inspection to factor them.
CHECK IT OUT!!!
INSPECTION METHOD
­ here's how it goes... "What two numbers?"
Adds to get "b"
Multiplies to get "c"
EXAMPLES...
SOLUTIONS
add
multiply
1) x2 + 13x ­ 48
(x ­ 3)(x + 16)
2) x2 ­ 10x ­ 24
(x ­ 12)(x + 2)
`
2(x ­ 7)(x ­ 3)
3) 2x2 ­ 20x + 42
1
October 04, 2016
y4+11y2+30
­4
x
3
x2 ­
2
y
6
+
y
z2 +5z
m2­8m+16
2
October 04, 2016
rk
o
W
1. x2+1x­6
multiply to give ­6.
Find two numbers that
add: to give 1
1. x2+1x­6
x2+4x­21
3
October 04, 2016
Another way to look at it:
1. x2+1x­6
What numbers multiply to give ­6?
What pair of factors could add
together to get 1?
list factors of 6:
1x6
-1 + -6
-1 + +6
+1 + -6
1+6
-2 + 3
2 + -3
2+3
2x3
-2 + -3
too much work
See next page for rules!!!!!!!!
x2 ­5x+6
So must be
1 6
2 3
only pair
that works
(x-2) (x-3)
are your factors
4
October 04, 2016
x2+5x­6
So must be
-1 +6
only pair
that works
-2 +3
(x-1) (x+6)
are your factors
5
October 04, 2016
Factor Each of the following:
(Finish For homework)
6
October 04, 2016
7