algebric expressions,identities are very importanat and are defined here

2. ALGEBRA IS A METHOD OF WRITTEN
CALCULATIONS that help us reason about
numbers. At the very outset, the student should
realize that algebra is a skill. And like any skill
-- driving a car, baking cookies, playing the
guitar -- it requires practice. A lot of practice.
Written practice. That said, let us begin.

4. • The first thing to noteis that in algebrawe useletters
as well as numbers. Butthe lettersrepresentnumbers.
We imitatethe rulesof arithmetic withletters, because
we meanthatthe rulewill betrue for any numbers.

5. Expressions, Identities,
Formulae, Equations

6. Expressions, Identities, Formulae, Equations
An expression…
Is an algebraic statement consisting of at least one variable and one
number. It has no equals sign and so cannot be solved.
An equation…
Is an algebraic statement consisting of an expression and a variable (or
another expression) separated by an equal symbol. It can be solved to
find the particular values of the variable for which it is true.
A formula…
Relates one variable (letter) to another. It consists of one variable and
an expression separated by an equal symbol.
An identity…
Is an equation that is always true for any variables (letter values) you
choose.

8. 1)Variable – A variable is a letter or symbol that
represents a number (unknown quantity).
Ex-
• 8 + n = 12
2)A variable can use any letter of the alphabet.
Ex-
• n + 5
• x – 7
• w - 25
Definitions

9. Definitions
3) Algebraic expression – a group of numbers,
symbols, and variables that express an
operation or a series of operations.
Ex- m + 8 , r – 3
4)Evaluate an algebraic expression – To find
the value of an algebraic expression by
substituting numbers for variables.
• m + 8 m = 2 2 + 8 = 10
• R – 3 r = 5 5 – 3 = 2

10. • Simplify – Combine like terms and
complete all operations
m = 2
• m + 8 + m 2 m + 8
• (2 x 2) + 8 4 + 8 = 12

11. Words That Lead to Addition in
algebra
•Sum
•More than
•Increased
•Plus
•Altogether

12. Words That Lead to
Subtraction in algebra
•Decreased
•Less
•Difference
•Minus
•How, many, more

14. Write an Algebraic Expression for
These Situations
• Scott’s brother is 2 years younger than
Scott
• The sum of two numbers is 12
• The difference between two numbers is 5
s - 2
v + c = 12
m – n = 5

15. Complete This Table
x x + 6
5
10
21
32
11
16
27
38

16. 48 y
2275 x
27)1(3 b
14264  aa
)73(5)2(4 2
7
 aa
722 2
k
01i
e
12 x
814
x
52
1
x
5.0sin x
ba 32 
1262
 xx
x
e
2
2
45sin 

17. 86)43(2  aa
baba
xxx 

aaa  52431
IRV 
maF 
rc 2
atuv 
a
acbb
x
2
42


2
mce 
n
x
x i

222
cba 
bcCosAcba 2222

aa 0
aa 1
cmxy 
10
x

18. Thank you
for your
attention