Introduction to AlgebraicExpressions
An algebraic expression is a mathematical phrase combining numbers, variables
(letters representing unknowns), and operation symbols (+, −, ×, ÷).
They help describe general arithmetic relationships and unknown quantities in
math.
Examples:
3x+23x+2,
a2−ba2−b,
4xy4xy
Expansion Question:
How are algebraic expressions different from arithmetic expressions?
3.
Components of AlgebraicExpressions
Constants: Fixed numbers (e.g., 7, −3, 1/2).
Variables: Symbols representing unknown or changing values (e.g., x,y,ax,y,a).
Coefficients: Numbers multiplying variables (e.g., 5 in 5x5x).
Operators: Symbols representing the operation (e.g., +, −, ×, ÷).
Elaboration:
Understanding these parts helps in simplifying and evaluating expressions correctly.
Expansion Question:
Given the expression 6ab−4b+c6ab−4b+c, identify the constants, variables, and
coefficients.
4.
Forms of AlgebraicExpressions
Monomial: One term
(e.g., 7x7x, −3a−3a, 8)
Binomial: Two terms
(e.g., x+5x+5, 3y−43y−4)
Trinomial: Three terms
(e.g., 2x2+3x+12x2+3x+1)
Polynomial: One or more terms (general
term including above)
Elaboration:
Terms are separated by plus or minus
signs.
Expansion Question:
Classify each as monomial,
binomial, trinomial, or
polynomial:
a) 4x34x3,
b) y+2zy+2z,
c) a2+b2+c2a2+b2+c2,
d) 5x2−3x+7−15x2−3x+7−1
5.
Examples of AlgebraicExpressions
3x+2y−7: 3 terms, variables xx, yy, constants and coefficients
4x−104x−10: binomial with variable xx
2x2−3xy+52x2−3xy+5: trinomial with degree 2
x+yx+y: binomial
5a+3b+c5a+3b+c: trinomial with three variables
Elaboration:
Identify variables, coefficients, and constants in each.
Expansion Question:
Write your own trinomial and explain each component.
6.
Operations on AlgebraicExpressions
Addition and Subtraction
Combine like terms (same variables and same powers):
(3x+2y)+(4x−y)=7x+y(3x+2y)+(4x−y)=7x+y
(5a−3b)−(2a+b)=3a−4b(5a−3b)−(2a+b)=3a−4b
7.
Operations on AlgebraicExpressions
Multiplication
Distributive Property:
2(x+5)=2x+102(x+5)=2x+10
Multiply monomials:
X*X=X^2
8.
Operations on AlgebraicExpressions
Division
Divide coefficients and subtract exponents:
X2/X=x
Triple Brackets
Multiply twobrackets first, then multiply the result with
the third.
(x+1)(x−2)(x+3)(x+1)(x−2)(x+3)Step 1:
(x+1)(x−2)=x2−x−2(x+1)(x−2)=x2−x−2Step 2:
(x2−x−2)(x+3)=x3+2x2−5x−6(x2−x−2)
(x+3)=x3+2x2−5x−6
11.
Practice Problems
Q1:Simplify 5x+3y−2x+45x+3y−2x+4
Q2: Evaluate 4x2−3x+74x2−3x+7 when x=2x=2
Q3: Identify the coefficient of yy in 8y−3x+68y−3x+6
Q4: Represent the sum of three consecutive integers as an algebraic
expression
Q5: Write and simplify an expression for the perimeter of a rectangle with
length ll and width ww
12.
Practice Problems
Q6:Expand and simplify (x+4)(x−5)(x+4)(x−5)
Q7: Expand and simplify (2x+3)(x−1)(2x+3)(x−1)
Q8: Expand and simplify (x+2)(x+3)(x−4)(x+2)(x+3)(x−4)
Q9: Expand and simplify (3x−1)(x+2)(x−3)(3x−1)(x+2)(x−3)
Q10: If A=(x+2)(x−3)A=(x+2)(x−3) and B=(x−1)B=(x−1), find and
simplify A×BA×B
13.
: Common Mistakesand Key Takeaways
Common Mistakes:
Combining unlike terms incorrectly
Incorrect use of distributive property
Ignoring exponent rules when multiplying/dividing powers
Key Takeaways:
Algebraic expressions generalize arithmetic by using variables.
Understanding components and operations is essential for simplifying and solving
problems.
Mastery of algebraic expressions is foundational for higher math topics.