2.3 Collecting like terms · Unit 2 Expressions, formulae and equations

1 · Teaching slidesuse ← → keys

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2 · Key words

like termsTerms containing exactly the same letter or letters to the same power, such as 3x and 5x.

collecting like termsAdding or subtracting like terms to write an expression more simply.

simplifyTo rewrite an expression in as short a form as possible.

termOne part of an expression, separated by + or −.

3 · Summary of the sectionrevise from this

Like terms contain exactly the same letters to the same powers.
Only like terms can be combined: 3x + 2x = 5x, but 3x + 4y cannot be simplified.
x and x² are not like terms.
Deal with each letter separately, and treat the plain numbers as another group.
Write algebra tidily: a not 1a, 2a not a + a, ab not b × a, a² not a × a.
A negative coefficient is fine: 4a − 7a = −3a.
For fraction terms, use a common denominator: 3a/4 + 5a/12 = 9a/12 + 5a/12 = 14a/12 = 7a/6.