Răspunsuri

Cel mai inteligent răspuns!
2014-10-11T22:29:32+03:00
A) X+2Y=    \left[\begin{array}{ccc}1&2\\3&4\\\end{array}\right]
X-2Y=  \left[\begin{array}{ccc}1&3\\5&7&\\\end{array}\right]
2Y, -2Y se reduc asa ca avem: 2X=  \left[\begin{array}{ccc}1&2&\\3&4\\\end{array}\right] +  \left[\begin{array}{ccc}1&3\\5&7\\\end{array}\right]
2X=  \left[\begin{array}{ccc}2&5\\8&11\\\end{array}\right]
X=  \left[\begin{array}{ccc}1& \frac{5}{2} \\4& \frac{11}{2} \\\end{array}\right]
Apoi inlocuim in prima sau a doua ecuatie pentru a-l afla pe Y, eu zic in prima:
2Y=  \left[\begin{array}{ccc}1&2\\3&4\\\end{array}\right] -   \left[\begin{array}{ccc}1& \frac{5}{2} \\4& \frac{11}{2} \\\end{array}\right]
 2Y=  \left[\begin{array}{ccc}0& \\ \frac{-1}{2} \\ -1&\frac{-3}{2} \\\end{array}\right] 

Y=  \left[\begin{array}{ccc}0& -1\\ \frac{-1}{2} &-3\\\end{array}\right]

La celalalt faci aptoape la fel, prima ecuatie o inmultesti cu -2, iar pe a doua cu 3
pentru a se reduce y
Succes!