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Algebraic ManipulationAQA GCSE Maths: Flashcards

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What does the notation 'ab' mean in algebra?

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What does the notation 'ab' mean in algebra?
ab means a × b (a multiplied by b). In algebra, we omit the multiplication sign between variables and numbers.
Define 'like terms' in algebraic expressions.
Like terms are terms that have the same variable(s) raised to the same power(s). For example, 3x and 5x are like terms, but 3x and 3x² are not.
Simplify: 4a + 7b - 2a + 3b
2a + 10b (Collect like terms: 4a - 2a = 2a and 7b + 3b = 10b)
Expand: 3(2x + 5)
6x + 15 (Multiply each term inside the bracket by 3)
What does it mean to factorise an expression?
Factorise means to write an expression as a product of its factors, usually by taking out the highest common factor (HCF) or grouping terms.
Factorise: x² + 7x + 12
(x + 3)(x + 4) (Find two numbers that multiply to give 12 and add to give 7)
Factorise: 2x² + 7x + 3
(2x + 1)(x + 3) (Use the AC method or trial and error for expressions of the form ax² + bx + c where a ≠ 1)
Complete the square for: x² + 6x + 5
(x + 3)² - 4 (Halve the coefficient of x to get 3, square it to get 9, then: (x + 3)² - 9 + 5 = (x + 3)² - 4)
Simplify: (6x²y) / (2xy)
3x (Cancel common factors: 6÷2 = 3, x²÷x = x, y÷y = 1)
What is the difference of two squares formula?
a² - b² = (a + b)(a - b) (This can be used to factorise expressions like x² - 9)
Factorise using the difference of two squares: x² - 25
(x + 5)(x - 5) (Recognise as x² - 5², so use a² - b² = (a + b)(a - b))
Rearrange the formula A = πr² to make r the subject.
r = √(A/π) (Divide both sides by π, then take the square root of both sides)
Rearrange v = u + at to make t the subject.
t = (v - u)/a (Subtract u from both sides, then divide by a)
Substitute a = 5, b = 3 into: 2ab + a²
2(5)(3) + 5² = 30 + 25 = 55
Expand: (x + 2)(x + 3)
x² + 5x + 6 (Use FOIL: x·x = x², x·3 + 2·x = 5x, 2·3 = 6)