Algebra is an essential part of mathematics that uses symbols, usually letters, to represent unknown values or numbers. **In algebra, we use these symbols, called variables, to create expressions that allow us to solve problems, manipulate numbers, and make predictions.**

One of the key features of algebra is that it allows us to represent relationships between different quantities using equations. These equations often contain variables and constants, which are fixed values. By manipulating these equations, we can find out the values of the variables and solve problems.

**For example, consider the equation:**

2x + 5 = 11

Here, **x is a variable** representing an unknown number. To solve this equation, we need to isolate the variable on one side of the equation by performing the same operation on both sides of the equation.

In this case, **we subtract 5 from both sides to get 2x = 6. **

Finally, we divide both sides by 2 to get x = 3.

Therefore, the **value of x is 3, and we have solved the equation.**

In this case, **we subtract 5 from both sides to get 2x = 6. **

Finally, **we divide both sides by 2 to get x = 3.** Therefore, the value of **x is 3,** and we have solved the equation.

Algebraic expressions are another important concept in algebra. An expression combines variables, constants, and mathematical operations, such as addition, subtraction, multiplication, and division.

For example:

**3x + 2y**

is an algebraic expression where x and y are **variables,** and 3 and 2 are **constants.**

To simplify algebraic expressions, we need to follow specific rules. One of the most important rules is the order of operations, which tells us which operation to perform first. The order of operations is as follows:

**Parentheses, Exponents, Multiplication and Division (from left to right), and Addition and Subtraction (from left to right).**

For example, **to simplify the expression:****3x + 2y - 4x - y**

we need to c**ombine like terms,** which are terms that have the same variables raised to the same power.

Here, **we can combine 3x and -4x to get -x, and 2y and -y to get y.**

Therefore, **the simplified expression is -x + y.**

Algebra has many applications in real-life situations, such as finance, science, engineering, and technology. For example, algebraic concepts are used to calculate interest rates, design bridges and buildings, analyse data, and model physical phenomena.

In summary, algebra is an essential part of mathematics that involves using variables and symbols to represent unknown quantities and create equations and expressions. By understanding and applying the rules of algebra, students can solve problems, simplify expressions, and gain a deeper understanding of the wider world around them.

## Revision Quiz

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