Maths questions

[Khoola29]

Hi,
I have been given mock Maths papers to look over in the Easter holidays in preparation for my GCSEs , but have come unstuck with several of the questions, and wonder if any of you could help? They are all algebra :-/
1. Show that x� + x� = 230.

2. x�-2mx = (x-m)� - k
i) Express k in terms of m.
ii) x�-2mx has a minmum value as x varies.
i)Find the minimum value of x�-2mx in terms of m.
ii)State the value of x for which this minimum value occurs in terms of m.

Thank you VERY much!!
Katie xxxx

[henrymullen]

Icould give you all the right answers but that would be CHEATING

[Khoola29]

No, I'm asking because I don't know how to do the questions, and as I have broken up for the Easter holidays already, I can't ask my teacher.

[juliefer]

I can't help you, Katie, but perhaps you should try posting your questions on the Science section. Or else try Googling 'algebra help' and looking through the websites that come up. Good luck.

[sohcahtoa]

2. (i) x2 � 2mx = (x-m)2 � k
x2 � 2mx = x2 � 2mx +m2 � k
x2 � 2mx - x2 + 2mx - m2 + k = 0
k = m2

(ii) Minimum value of (x-m)2 � m2 will be when (x-m)2 =0, i.e. when x=m.
Should question 1 not ask you to find x?