X,Y

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George+++
Euclid
Posts: 16
Joined: Thu Nov 20, 2008 5:42 pm

X,Y

Post by George+++ »

x,y=numere naturale -3x+5y=185 -aflati cemai mare valoare pentru 2x+8y.

problema de olimpiada judeteana la clasa a VI-a.succes
Last edited by George+++ on Tue Nov 25, 2008 8:15 pm, edited 1 time in total.
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Marius Dragoi
Thales
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Joined: Thu Jan 31, 2008 5:57 pm
Location: Bucharest

Post by Marius Dragoi »

\( 12x + 20y = 740 \) \( \Rightarrow \) \( 5(x+4y) + 7x = 740 \)
\( 2(x+4y) \) maxim \( \Leftrightarrow \) \( x+4y \) maxim \( \Leftrightarrow \) \( 7x \) minim \( \Rightarrow \) \( x=0 \) \( \Rightarrow \) \( x+4y = 148 \) \( \Rightarrow \) \( 2x+8y=296 \).
Last edited by Marius Dragoi on Tue Nov 25, 2008 8:39 pm, edited 1 time in total.
Politehnica University of Bucharest
The Faculty of Automatic Control and Computers
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Marcelina Popa
Bernoulli
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Post by Marcelina Popa »

Lipseste o informatie. Ca x si y sunt naturale, presupun.

Marius, n-ai inmultit bine cu 4 ambii mebri: \( 3\cdot 4 =12 \), nu \( 15 \) :)
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George+++
Euclid
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Joined: Thu Nov 20, 2008 5:42 pm

Post by George+++ »

.. :)
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George+++
Euclid
Posts: 16
Joined: Thu Nov 20, 2008 5:42 pm

Post by George+++ »

uite una mai explicita:y=185-3x:3
=37-3x:5
=>x=5k
y=37-3k,k_<12
2x+8y=2*5k+8(37-3k)
=10k+296-24k
=296-14k de unde cea mai mare valoare este cand k=0
=>296.
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