Expressions in math are combinations of numbers, variables, operators, and sometimes parentheses that represent a particular value. An expression is a statement involving at least two different numbers or variables and at least one operation, such as addition, subtraction, multiplication, division, exponents, and roots.
An expression in mathematics is a finite combination of constant or variable using operators such as addition (+), subtraction (-), multiplication (×), or division (÷).
Unlike equations, expressions do not contain an equality sign ('='). Some examples of expression include:
- 2x + 3y
- 5a − 2b
- 3/4 x + 2
- 7 + 2 × 5
Some key points regarding expressions are:
- Expressions do not contain an equality sign ("=")
- Constants, variables, or products of variables and constants are considered terms
- When a variable is multiplied by a constant, the constant is referred to as a coefficient
Terms used to Explain Expression
Some common terms used in the explanation of expression are:
- Variable
- Constant
- Coefficients
Variable
A symbol that has variable values or that can be assigned different numerical values is called a variable in an algebraic expression.
Typically, a letter from the English alphabet is used to represent a variable. For instance, x, y, z, i, c or a, b, c, etc.
Constant
A symbol in an algebraic expression with a fixed numerical value is called a constant.
For instance, 7, -5, and 0, 3/5, etc. are all constants.
Coefficients
In mathematics, a coefficients are a multiplicative factor involving a number or a variable in the term of a polynomial, series, or expression.
Coefficients can be either numeric values (constants) or letters standing for constants. For instance, in the term 7x, the coefficient is 7, and in -9y2, the coefficient is -9.
Note: Coefficients can be positive, negative, real, complex, rational, irrational, decimal, or fractional.
How to Write Expression in Math?
To write an expression in math, you need to use a combination of numbers, variables, and operational symbols.
Step 1: Interpret the given text or phrase, identifying key words related to arithmetic operations (e.g., addition, subtraction, multiplication, division)
Step 2: Replace those key words with appropriate mathematical symbols (e.g.,+,-,×,÷).
- and with "+"
- from with "-"
- of with "×"
- by with "÷"
Step 3: Apply the order of operations when necessary, especially when dealing with multiple operations in a single expression.
Step 4: Simply to obtain the final Expression.
For example, to write the expression for "The sum of 7 and the product of -2 and x": 7 + (−2 × x) = 7 - 2x
Types of Expression
Expressions are mathematical statements that combine variables, constants, and operators. There are different types of expressions, including:
- Numerical Expression
- Algebraic Expression
- Radical Expression
- Fractional Expression
Numerical Expression
A numerical expression is a specific type of mathematical expression that involves numerals (constants) and arithmetic operations.
It produces a result that is either a number or a Boolean value when evaluated. Some examples of numerical expressions include:
- 5 - 2 + 1/2 (a simple constant expression)
- 5 + 2 - (3 × (-1) + 7) (this can be simplified to 3)
- 3 × (8 + 4) - 7 (this can be simplified to 29)
Algebraic Expression
An algebraic Expression is a mathematical expression that consists of variables, constants, and algebraic operations such as addition, subtraction, multiplication, division, and exponentiation.
Some examples of algebraic expression are:
- 3x - 3xy3 (monomial expression)
- 5xy + 8 (binomial expressions)
- ax + by + c (polynomial expressions)
Fractional Expression
A fractional Expression contains fractions within an algebraic expression. For instance, consider the following examples:
- 3/x + 9/20
- (x - 2)/(x + 2) + 2
- 3/(x - 3) - 1/2
- 4x2/(x - 5)
Radical Expression
A radical expression is a mathematical expression that contains a root symbol, such as a square root, cube root, or fourth root. Examples of radical expression include:
- 3√(2) - 7
- √(9x2) + 1/2
- √(x2 + 2x - 1)
Examples of Expression
There can be various examples of expression involving various functions, constant or variable. Some common examples include:
Polynomial Expression
All the expression of form with any degree is called polynomial expression. Some examples of polynomial expressions include:
- 2x2 + 3x + 7
- a2 + 2ab + b2
- x4 - 2xy2 + 3y4
- x3 - 8x - 11
- 3x2 - 5x3 + 8x + 9x2 - 7x + 2x3
- 2p2 - 7
- 6m3 - mn + n2 - 4
Trigonometric Expression
Expression containing trigonometric ratios is called trigonometric expression. Examples of trigonometric expression are:
- sin2x - 2sin x
- sin x + cos x + tan x
- sin3x - sin2x + sin x
\frac{tan \theta}{\cosec \theta} + \frac{sin \theta}{\cot \theta} + \frac{cos \theta}{\cot \theta}
Logarithmic Expression
A logarithmic expression typically includes a logarithm function, denoted as either logb (x), where b represents the base of the logarithm. Some examples are:
- log10 100 - log10 10 + log10 2
- ln x + ln y -ln 2
- logπ (π2) - log10 100
Exponential Expression
Exponential expressions involve exponents and are used to represent repeated multiplication. Some examples of exponential expression are:
- 23 - 32 + 75
- 103 -102
Factors of Expression
A factors of an expression is a number or expression that divides the expression evenly.
For example, in the expression 2x + 4, both 2 and x + 2 are factors of the expression. Some more examples of factors of expression are:
- For 3ab + 6c, factors are 3 and ab + 2c.
- For x2 - 5x + 6, (x - 2) and(x - 3) are the factors.
- For 2ab - 6ab2, 2b and a + 3ab are the factors.
Equation vs Expressions in Math
Key difference in equations and expression in math is given below:
| Feature | Equation | Expression |
|---|---|---|
| Structure | Two expressions connected by an "equal to" (=) sign. | Combination of numbers, variables, and operation symbols. |
| Number of expressions | Two | One |
| Purpose | Represents an equality between two mathematical statements. | Represents a value or a calculation without requiring equality. |
| Solution | Often solved to find a specific value for a variable. | Can be simplified to obtain a final value. |
| Example | 2x + 5 = 11 | 3x2 - 2y |
| Real-world use | Balancing chemical equations, finding distances, calculating speed, etc. | Representing areas, sums, volumes, etc. |
Articles Related to Expressions in Math:
Solved Examples on Expressions
Example 1: Find the coefficient of term 7y in the expression 6x2+ 7y + 3.
Solution:
Coefficient of term 7y in the expression 6x2+7y +3 is "7".
Example 2: Find the terms in the expression 5x +6y +3.
Solution:
No. of terms in the expression is 5x , 6y, 3.
Example 3: Find the factors in the expression 7x3+ 5x2+ 6x + 2.
Solution:
Factors in the expression are 7, x3, 5, x2, 6, x, 2.
Example 4: What type of algebraic expression is 4x + 5?
Solution:
4x + 5 has two monomials 4x and 5 and hence it is a binomial. Now, since every binomial is a type of polynomial.
Therefore, 4x + 5 is a binomial.
Example 5: Identify the terms and coefficients in the expression 3a2 +2ab.
Solution:
There are two terms in the expression 3a2, 2ab.
Coefficients in the expression are 3, 2.