Expanding Double Brackets Flashcards

GCSE Mathematics (Edexcel) 1MA1

Expanding double brackets

Multiply each term in the first bracket by each term in the second bracket, then simplify by combining like terms.

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Expanding double brackets

Multiply each term in the first bracket by each term in the second bracket, then simplify by combining like terms.

FOIL method

A method for expanding double brackets: First, Outer, Inner, Last.

Example: Expand (x + 3)(x + 2)

x² + 2x + 3x + 6 = x² + 5x + 6.

Example: Expand (x - 4)(x + 5)

x² + 5x - 4x - 20 = x² + x - 20.

Example: Expand (2x + 1)(x - 3)

2x² - 6x + x - 3 = 2x² - 5x - 3.

Example: Expand (x - 2)(x - 7)

x² - 7x - 2x + 14 = x² - 9x + 14.

What does 'like terms' mean?

Terms with the same variable and power, e.g., 3x and 5x are like terms.

Expanding (x + a)(x + b) general form

x² + (a + b)x + ab.

Expanding (ax + b)(cx + d) general form

acx² + (ad + bc)x + bd.

Common mistake when expanding double brackets

Forgetting to multiply all terms in the first bracket by all terms in the second bracket.

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