## Algebraic Expressions

What are Algebraic expressions?
Algebraic expressions are formed by terms which contain both variables and constants. A term is a constant or a product of two or more constants and variables.
Eg:-  4x+5, 5y-9, 6p+35, etc.

Monomials, Binomials  and Polynomials
An Algrebraic expression is said to be a monomial if it contains only one term. Ex :- 8axyz, 5a2b2
An Algrebraic expression is said to be a bionomial if it contains two unlike terms. Ex :-  ax + b, 30a + b
An Algrebraic expression is said to be a trinomial if it contains three unlike terms. Ex :-   2p2 + 8q2 + 3r2

Addition of two algebraic expression can be done in this way

6ax+11by+17cz+15
8ax             -8cz+13
14ax+11by+9cz+28

Subtraction of Algebraic Expressions
Subraction of two algebraic expression can be done in this way
Q2. Subtract 12x+7y-15z from 17x+8y-15z

17x+8y-15z
12x+7y-15z
(-)   (-)  (+)
5x + y

Multiplication of Algebraic Expressions
Multiplication of two algebraic expression can be done in this way
Q3.  Multiply (2ab+3bc+8ca) by 7abc

7abc (2ab+3bc+8ca)
= 7abc(2ab)+7abc(3bc) + 7abc (8ca)
=14a2b2c+ 21ab2c+ 56a2bc2

Q4.  Multiply (15mn+12m) and (3mn+8n)

(15mn+12m)(3mn+8n)
15mn (3mn+8n)+12m (3mn+8n)
=45m2n+ 120mn+ 36m2n + 96mn

Standard Indentities

Indentity I -  (a + b)2 = a2 + 2ab + b
Indentity II -  (a - b)2 = a2 - 2ab + b
Indentity III -  a2 - b2 = (a- b) (a +b)

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