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# P1 - Algebra Q watch

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1. Stuck on this Q.... If anyone can be bothered enough, plz help! I don't like proof questions.

E=(x-3y)^2 - x(x-6y) + 2
a) Prove that E is independent of x.
b) Find the least value of E and the value of y for which this occurs.
2. (Original post by Mikan18)
Stuck on this Q.... If anyone can be bothered enough, plz help! I don't like proof questions.

E=(x-3y)^2 - x(x-6y) + 2
a) Prove that E is independent of x.
b) Find the least value of E and the value of y for which this occurs.
a Expand it so its x62 - 6xy + 9y^2 - x^2 + 6xy + 2 so all the xs cancel, That proves that e is independent of x

bjust differentiate and put it equals to 0, and the minimum value is the least yalye of e. if you know the value of e you can in turns find why by putting it in the original equation
3. (Original post by Mikan18)
Stuck on this Q.... If anyone can be bothered enough, plz help! I don't like proof questions.

E=(x-3y)^2 - x(x-6y) + 2
a) Prove that E is independent of x.
b) Find the least value of E and the value of y for which this occurs.
For (a) expand out the brackets and as E independant of x, there should be no x left in the formula, therefore showing that E is independent of x
4. Did this a few days ago

5. Thanks a lot all.

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