6.1 Reasoning in Algebra and Geometry Notes.notebook
Warm ­ Up
1. Evaluate the piecewise function.
2. Graph the piecewise function.
3. Write your answer to #17.
January 23, 2015
6.1 Reasoning in Algebra and Geometry Notes.notebook
January 23, 2015
6.1 Reasoning in Algebra and Geometry Notes.notebook
January 23, 2015
What property of equality is used?
a. AR TY
3. ST QR
TY AR
QR ST
pg. 397
b. 3(x+5) = 9
3x+15=9
c. 1/4 x = 7
x = 28
d. m < R = m < R
4. AB ­ BC = 12
AB = 12 + BC
6.1 Reasoning in Algebra and Geometry Notes.notebook
January 23, 2015
We will use the properties to PROVE mathematical statements. A proof has the steps (statements) on the left side and the properties you use on the right side.
pg. 398
pg. 396
Given: 1/2 x ­ 5 = 10 JUSTIFY EACH STEP
2(1/2x­5)=20 a._________________
x­10=20
b.__________________
x=30
c.__________________
6.1 Reasoning in Algebra and Geometry Notes.notebook
January 23, 2015
Ex: What is the value of x? Justify each step.
Given: AB bisects < RAN
x0
(2x­75)0
6.1 Reasoning in Algebra and Geometry Notes.notebook
3n
3(n+4)
X
January 23, 2015
Z
Y
Given: XY = 42 Justify each step
XZ+ZY=XY
a.__________________
3(n+4)+3n=42 b._________________
3n+12+3n=42 c._________________
6n+12=42
d. _________________
6n=30
e. _________________
n=5
f. _________________
6.1 Reasoning in Algebra and Geometry Notes.notebook
January 23, 2015
Given: C is the midpoint of AD.
Prove: x = 6
4x
2x+12
C
A
D
Write a two­column proof.
GIVEN: AB CD
Prove: AC BD
A
B
C
D
6.1 Reasoning in Algebra and Geometry Notes.notebook
January 23, 2015