Algebra 1 Lessons

Algebra 1 Lessons Types of symbols that are used in algebra: - In algebra 1 lessons, we come across two types of symbols, namely Constants Variables. Definition of constant: - A symbol which has a fixed numerical value in all situations is known as a constant. For example: - 5, 30, 246, -7, 5 / 3, 7 / 9, 80.5, -9.6, etc. Whereas a symbol whose value changes with situation is known as a variable, such as; x, y, p, q, 5x, 7z, etc Note: - In 3 x, 3 is a constant and x is variable but together 3 x is a variable. Reason: - As the value of x will change so the value of 3x will also change. Similarly, 3 is a constant and x is variable but together each of 3 + x, x 3, x 3, etc. is a variable. So, we can say that every combination of a constant and a variable is always a variable. This combination of constant and variable is known as an expression and the value of the expression depend on the value (s) of its variable (s). 3 + x x 3 x 3 Example 1: Solve for x in the equation 5x 15 = 20 For a given equation if the value of a variable is unknown, then the equation is solved to find the value of the variable. Different algebraic operations are used in order to solve the given equation. 5x 15 = 20 Add 15 on both sides of the equation. 5x -15 +15 = 20 + 15 5x = 35 Now, divide by 5 on both sides of the equation. 5x/5 = 35/5; x = 7 Hence the value of the unknown variable x is 7 Example 2: If x = 0, the value of the expression x 3 For a given equation, the value can be calculated by plugging the value of variable in the equation x-3 = 0 3 = - 3