How do you factor w^2 + 14w-1632=0w2+14w1632=0?

1 Answer
Jul 19, 2016

(w-34)(w+48) = 0(w34)(w+48)=0

Explanation:

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Method 1 - Completing the square

0 = w^2+14w-16320=w2+14w1632

= (w+7)^2-49-1632=(w+7)2491632

= (w+7)^2-1681=(w+7)21681

= (w+7)^2-41^2=(w+7)2412

= ((w+7)-41))((w+7)+41)=((w+7)41))((w+7)+41)

= (w-34)(w+48)=(w34)(w+48)

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Method 2 - Find pair of factors

We want to find a pair of factors of 16321632 which differ by 1414.

Since 1414 is somewhat smaller than 16321632 they will be approximately sqrt(1632)-716327 and sqrt(1632)+71632+7.

Note that 40^2 = 1600402=1600 and 41^2 = 1681412=1681

So:

sqrt(1632) ~~ 41.5163241.5

sqrt(1632)-7 ~~ 34.51632734.5

sqrt(1632)+7 ~~ 48.51632+748.5

Of the nearby numbers, find that 3434 and 4848 are both factors of 16321632 and they differ by 1414, so:

w^2+14w-1632 = (w+48)(w-34)w2+14w1632=(w+48)(w34)