How do I expand a factorised expression?
Take example (x+3)(x-4) We use FOIL - first, outer, inner, last We multiply each part by the other part. First -> x times x = x2 . Outer -> x times -4 = -4x (remember the minus infront of the 4), Inner -> 3 times x = 3x. Last - -4 times 3 = -12 (again, remember minus infront of the 4) We then add the four answers from FOIL together: x2-4x+3x-12 From here we can simplify: x2-x-12
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