Edexcel IGCSE Maths 复习笔记 2.3.3 Expanding Three Brackets

Edexcel IGCSE Maths 复习笔记 2.3.3 Expanding Three Brackets

Expanding three brackets

  • We’re still following the basic principle of expanding here – get rid of the brackets by multiplying out
  • We just need a good method to make sure everything gets multiplied by everything else in the correct way

Beware of minus signs

  • Remember the basic rules: 

    “ − × − = + ”“ − × + = − ”

How to multiply out three brackets

  • Multiply out one pair of brackets using FOIL (as for two brackets)
  • If the new bracket has two terms use FOIL (again!)
  • Otherwise link each term in the smaller bracket to each term in the larger bracket (that’s six links in total)
  • Write down the six multiplications
  • Careful here – you have to be sure to include any minus signs!
  • Simplify by collecting like terms (if there are any)

Worked Example

转载自savemyexam
更多IGCSE课程
翰林国际教育资讯二维码