Grade 8 ↓
Algebra
Algebra is a branch of mathematics that uses numbers, symbols, and letters to represent and solve problems. It is a powerful tool that helps in understanding and solving all kinds of mathematical problems and is widely used in various fields such as engineering, science, and technology.
Algebraic expression
Algebraic expressions are combinations of numbers, variables, and operators. For example:
3x + 4
In this expression, 3
is the coefficient, x
is the variable, and 4
is the constant.
Variables and constants
In algebra, variables are symbols that represent unknown values and can change, while constants are fixed values. In the expression 5y - 7
:
y
is a variable.5
is the coefficient ofy
.-7
is a constant.
Simplification of algebraic expressions
Simplifying an expression means combining like terms. Like variables in like terms are raised to the same power. Here is how to simplify:
2x + 3x + 4 = 5x + 4
Operations on algebraic expressions
Add
Adding algebraic expressions involves combining like terms:
(2a + 3b) + (4a - b) = 6a + 2b
Subtraction
Subtraction also involves combining like terms, but we must distribute the negative sign:
(5x + 6y) - (3x - 2y) = 2x + 8y
Multiplication
For multiplication, distribute each term of one expression into each term of the other expression:
(x + 2)(x + 3) = x 2 + 5x + 6
Division
Division involves dividing the expression by the divisor:
frac{6x^2 + 9x}{3x} = 2x + 3
Solving algebraic equations
An equation is a mathematical statement that asserts the equality of two expressions. Solving an equation means finding the value of the variable that makes the equation true:
Linear equations
These are equations of the first degree, such as:
2x + 3 = 7
To solve this, subtract 3
from both sides:
2x = 4
Then, divide by 2
:
x = 2
Quadratic equations
These are second-degree equations, such as:
x^2 + 5x + 6 = 0
These are usually solved by factoring, completing the square, or using the quadratic formula:
x = frac{-b pm sqrt{b^2 - 4ac}}{2a}
Using algebra to solve real-world problems
Algebra is a practical tool for solving real-world problems. Consider a scenario where you need to calculate distance, area, or even a financial budget.
Example: Calculating distance
Suppose you have the rate of speed and time, you can find the distance using the formula:
Distance = Speed times Time
Let's find the distance traveled at 60 mph for 3 hours:
Distance = 60 times 3 = 180 miles
Example: Solving financial problems
Suppose you want to calculate your savings from your monthly income:
Income = Savings + Expenses
If your income is $2000 and expenses are $1500, find your savings:
2000 = Savings + 1500
Savings = 500
This is just the beginning!
Algebra is a foundational concept in mathematics that opens the door to more advanced mathematical theories and practical applications. With a solid understanding of the basic concepts discussed here, including expressions, equations, and real-world problem solving, you are preparing yourself for success in future math courses and in everyday life!