An equation is a mathematical statement that shows two expressions are equal. It uses an equals sign (=). For example: 2 + 3 = 5.
Equations can also contain unknown values called variables:

Types
Some key equation types in mathematics include linear equations, quadratic equations, polynomial equations, logarithmic equations, and exponential equations.
1. Linear Equations
The linear equation is an equation that contains a constant, variable, or product of a constant and shows the relationship between variables and a constant. Linear equations can be represented on a single-line graph.
The general form of a linear equation is:
Ax + By = C ,where A, B, and C are constants, with A and B are not equal to zero.
Example:
- Linear Equation in One Variable: 2x + 10 = 0
- Linear equation in Two Variables: 2x + 3y - 10 = 0
2. Quadratic Equations
In a quadratic equation, a variable gets raised to the power of 2, making a U-shaped curve when graphed.
A quadratic equation can be written as
Ax2+ Bx + C = 0 ,where A, B and C are constant and A ≠ 0.
Example:
2x2 + 3x - 10 = 0 , where, A = 2, B = 3, C = -10.
3. Polynomial Equations
A polynomial equation is a mathematical expression that includes variables, exponents (such as squares and cubes), and coefficients (numbers). The degree of the equation depends on the highest exponent present. When the highest exponent (or power) of any variable is 2, then a quadratic equation will be formed.
The general form of the polynomial equation is given as:
anxn + a(n-1)x(n-1) + ......+ a1x + a0 = 0
Where,
- an, a(n-1),....., a1, a0 are coefficients.
- x is a variable.
- n is a whole number that can't be negative and shows the highest degree of the polynomial.
4. Logarithmic Equations
Logarithmic equations use logarithmic functions, which are the reverse of exponential functions. In other words, these equations help us solve for the unknown variable that is found as an exponent in an exponential expression. The general form of a logarithmic equation is:
y = logb(x)
Where,
- log represents the logarithm.
- x is the number which needs to find.
- b is the base of the logarithm, and a positive number which is greater than 1.
- y is the result or exponent to which the base b must be raised to get x.
5. Exponential Equations
An exponential equation is a math equation that uses an exponential function. This type of equation can be written as:
f(x) = ax
The general form of an exponential equation is:
f(x) = a.ekx
Where,
- f(x) represents the value of the function at a given x
- a is the initial value or the function's value at x = 0.
- e is the base of natural logarithms (approximately 2.71828).
- k is a constant that determines the rate of growth or decay.
- x is the variable, which can take different values.
Solving Equations
Solving an equation means finding the value(s) of the variable that make both sides of the equation equal.
General Steps to Solve an Equation
Step 1: Simplify Both Sides
- Remove brackets using distributive property.
- Combine like terms, if possible.
Step 2: Isolate the Variable
- Move variable terms to one side and constants to the other side.
- Perform the same operation on both sides to maintain equality.
Step 3: Solve for the Variable
- Use addition, subtraction, multiplication, or division to find the value of the variable.
Step 4: Verify the Solution
- Substitute the obtained value back into the original equation.
- Check whether the left-hand side (LHS) equals the right-hand side (RHS).
Applications
- Equations serve as tools to describe diverse aspects of the natural world, encompassing everything from the movement of objects to the principles governing electricity and even the intricate realm of quantum mechanics.
- Engineers play a vital role in various fields, using their expertise to design structures, electrical circuits, and mechanical systems.
- Mathematical equations have practical uses in economics as they help model economic trends, analyze supply-demand relationships, and study the dynamics of financial markets.
- Financial professionals use equations to calculate interest rates and investment returns and to assess and manage financial risks.
- Equations form the foundation of algorithms in computer science, enabling tasks such as data analysis and encryption.