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secondary 2 | Maths
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not sure how to do qn14 and 15
Date Posted: 5 years ago
Views: 273
14i) Expand p(p-4q) first. You get p² - 4pq. It is easy to simplify.
For 15 i), Remember that a² - b² = (a + b)(a - b). Use this property to convert (n-a)(n+a).Then you'll realise it can be simplified easily from there.
As for 14ii) and 15ii, notice the expressions are very similar to their i). It is quite easy to find a suitable value of p and q (and n and a for 15ii) if you compare term for term and equate them.
For example, in 14ii) , 5310² = (p - 2q)²,
5330 = p and 5290 = (p - 4q). It is easy to find out what is p and q.
Once you figure out the suitable values to use, subatitute them into the simplified expression in i) to get your answer
For 15 i), Remember that a² - b² = (a + b)(a - b). Use this property to convert (n-a)(n+a).Then you'll realise it can be simplified easily from there.
As for 14ii) and 15ii, notice the expressions are very similar to their i). It is quite easy to find a suitable value of p and q (and n and a for 15ii) if you compare term for term and equate them.
For example, in 14ii) , 5310² = (p - 2q)²,
5330 = p and 5290 = (p - 4q). It is easy to find out what is p and q.
Once you figure out the suitable values to use, subatitute them into the simplified expression in i) to get your answer
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