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secondary 3 | A Maths
2 Answers Below
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How??
Date Posted: 3 years ago
Views: 294
Nic, when two parts are labelled (a) and (b), usually they are not related. But when they are labelled (i) and (ii), they are linked to each other.
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done
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Hope this helps!
Date Posted:
3 years ago
Omg yes thank you!!! I was thinking how part (i) was linked to part (ii) and you answered it!
Part i is not supposed to be done that way in A Maths. The expression should not be expanded right from the start. You are likely to be deducted marks for it.
Nic, follow this formula
a3 - b3
= (a - b) (a2 + ab + b2)
(x + 3)^3 - x^3
= (x + 3 - x) [(x + 3)^2 + (x + 3)(x) + x^2]
= 3 (x2 + 6x + 9 + x2 + 3x + x2)
= 3 (3x2 + 9x + 9)
= 9 (x2 + 3x + 3)
Nic, follow this formula
a3 - b3
= (a - b) (a2 + ab + b2)
(x + 3)^3 - x^3
= (x + 3 - x) [(x + 3)^2 + (x + 3)(x) + x^2]
= 3 (x2 + 6x + 9 + x2 + 3x + x2)
= 3 (3x2 + 9x + 9)
= 9 (x2 + 3x + 3)
Hi Eric! I actually did part (i) on my own already before I asked this question. I just needed help
With part (ii). But yes my working is exactly the same as the one you typed out! Thankss
With part (ii). But yes my working is exactly the same as the one you typed out! Thankss
done
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Hihi
Date Posted:
3 years ago
Thank you!!
Similar to the comment I left on the previous tutor, factorisation should be directly performed on the starting expression in the spirit of the subject.
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