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Maths

Re-arranging symbols

In algebra, we often get very long expressions that we need to make simpler. Simpler expressions are easier to solve.

Collecting like terms

To simplify an expression, we collect like terms.

Look at the expression: 4x + 5x -2 - 2x + 7

To simplify:

  • The x terms can be collected together to give 7x.
  • The numbers can be collected together to give 5.

So 4x + 5x -2 - 2x + 7 simplified is 7x + 5.

Remember that terms are separated by + and - signs, and these are always attached to the front of a term.

Question

Simplify this expression: x + 5 + 3x- 7 + 9x+ 3 - 4x

toggle answer

Answer

To work it out:

  • Write down the expression
  • x + 5 + 3x - 7 + 9x + 3 - 4x
  • Collect all the terms together which are alike. Remember that each term comes with an operation (+, -) which goes before it.
  • x + 3x + 9x - 4x + 5 - 7 + 3
  • Simplify the x terms.
  • x + 3x + 9x - 4x = 9x
  • Simplify the numbers separately.
  • 5 - 7 + 3 = 1

Answer: x + 5 + 3x - 7 + 9x + 3 - 4x can be simplified to 9x + 1

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