Expressions, Equations and IdentitiesEdexcel GCSE Maths: Flashcards
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What does 3y mean in algebra?
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- What does 3y mean in algebra?
- y + y + y (three lots of y), not y × y × y.
- What does ab mean?
- a × b.
- What is the difference between an expression and an equation?
- An expression has no equals sign; an equation states that two expressions are equal (true for specific values).
- What symbol is used to show an identity?
- ≡ (the 'identical to' sign).
- Is x² − 1 ≡ (x−1)(x+1) an equation or an identity?
- An identity — it is true for every value of x.
- What is a formula?
- An equation that links two or more variables, e.g. A = πr².
- What are 'like terms'?
- Terms with exactly the same variable(s) raised to the same power.
- Simplify 5x + 3y − 2x + y.
- 3x + 4y.
- If a = 4 and b = −2, evaluate a² + 3b.
- 16 − 6 = 10.
- How do you prove two expressions are equivalent?
- Expand and simplify one side until it matches the other exactly.
- Why must you use brackets when substituting a negative number into a squared term?
- Because (−2)² = 4, but −2² is often wrongly read as −4.
- Show that 2(x+3) + x is equivalent to 3x + 6.
- 2(x+3)+x = 2x+6+x = 3x+6, which matches — so the identity holds.
- What does a/b mean?
- a ÷ b.