OCR MEI - January 2001 - Question 1



So this question is obviously about basic algebra and we just need to follow the instructions in the question and expand the brackets.

(1 - 2x)(1 - 2x)(1 - 2x)

So I'm going to use what you might know as the "smiley face method" or the "foil method".



We're just going to multiply together the first two sets of brackets first so I'm going to leave out the last bracket for now.

(1 - 2x)(1 - 2x)
= 1 - 2x - 2x + 4x2
= 1 - 4x + 4x2

So now all we need to do is multiply what we've got above with the last bracket.

(1 - 4x + 4x2)(1 - 2x)

 We're going to times the whole first bracket by 1 first and then by -2x.

= 1 - 2x - 2x + 4x2 - 2x + 4x2 + 4x2 - 8x3

 As the question tells us to simplify, we're going to collect like terms. Always simplify where possible in exam questions, even if it doesn't tell you to.

= 1 - 6x + 12x2 - 8x3

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