1can some1 pls factorise this expression?
The minimum value of
x2 + 2xy + 3y2 – 6x – 2y, where x, y are Real , is equal
to
(a) –9
(b) –11
(c) –12
(d) –10
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8 Answers
21i dont think there is an immediate conclusion from writing it as (x+y)^2-6(x+y)+2y^2+4y
other than (x+y-3)^2 + 2(y+1)^2 -11
:D
11A quadratic whose leading coefficient is positive is minimised at x=-b2a.
(x+y)2-6(x+y)≥-9
same logic for 2y2+4y≥-2
sigh :-(
1can some1 pls post more sums of this type in this thread.
i have to improve my "factoisational" skills.
