C14. (Intro) Further Solving of Equations and Inequalities

By: Fatmawati, S.Si., M.Ed., Gr.

​Cambridge IGCSE 0580

Algebra is a branch of mathematics that uses symbols (usually letters) to represent numbers in formulas and equations.

Cambridge IGCSE 0580

• In many ways, learning algebra is much like learning any other language.

• Just like sentences use words to describe thoughts, algebra uses expressions to describe patterns and relationships.

Cambridge IGCSE 0580

• In algebra, a letter is often used to stand for a number.

• The letter used ​to stand for a number is called a variable.

  • Some common letters used as variables​ are x, y, z, a, b, c, and n. ​

• When a letter is used to stand for a number, the number is unknown. Think of those letters as "mystery numbers."

• ​A variable can be a part of an expression, an equation, or an inequality.

• An expression is part of a mathematical sentence, just as a phrase is ​part of an English sentence.

  • 2n + 4 ; 3y ; 6 + x

• A mathematical sentence ​contains two expressions joined by an equal sign or an inequality sign.

  • 2h + 4 ≥ 13​ ; p + 4 = 9

• An equation is a mathematical sentence in which two expressions are joined by an equal sign. ​

  • ​c - 8 = 1 ; 4t + 9 = 17

Cambridge IGCSE 0580

• ​An inequality is a mathematical statement in which two phrases are joined by an inequality symbol.

  • < "less than"

  • > "greater than"

  • ≤ "less than or equal to"

  • ​≥ "greater than or equal to"

  • ​Examples:

    • 3a < 9 ; f ≥ 4

Intro to Algebra | Robinson

By Fatmawati Fatmawati