Take the 2-minute tour ×
Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

Possible Duplicate:
Solution of 3 equations in 3 unknowns

Find the value of c which makes it possible to solve. $$\left\{\begin{array} {c} u + v + 2w = 2\\ 2u + 3v - w = 5\\ 3u + 4v + w = c \end{array}\right.$$

share|improve this question
Hint: the equation says that $(2,5,c)$ is a linear combination of $(1,2,3)$, $(1,3,4)$, and $(2,-1,1)$. Can you describe the set of such linear combinations (and its dimension)? –  Marc van Leeuwen Oct 9 '12 at 11:36
Please STOP Reposting this question. There have been 7+ copies in the last hour. –  Ragib Zaman Oct 9 '12 at 11:37
add comment

marked as duplicate by Henry, Henning Makholm, Brian M. Scott, Ragib Zaman, Martin Sleziak Oct 9 '12 at 11:49

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

1 Answer

Add equations 1 and 2 to get

$$3u +4v + w = 7.$$

Compare to equation 3, you get $c=7$.

share|improve this answer
add comment

Not the answer you're looking for? Browse other questions tagged or ask your own question.