Question

Solve the equations
x+y+z=1, 2x+2y + 3z=6,
x+4y+9z=3 using Cramer's method.​

Answer 1

Answer:

$(7,-10,4)$

Step-by-step explanation:

Forming the matrix

$\left[\begin{array}{ccc}1&1&1\\2&2&3\\1&4&9\end{array}\right] \left[\begin{array}{c}x\\y\\z\end{array}\right] =\left[\begin{array}{c}1\\6\\3\end{array}\right]\\\left[\begin{array}{c}x\\y\\z\end{array}\right]=\left[\begin{array}{ccc}1&1&1\\2&2&3\\1&4&9\end{array}\right]^{-1}\left[\begin{array}{c}1\\6\\3\end{array}\right]\\\left[\begin{array}{c}x\\y\\z\end{array}\right]=\left[\begin{array}{ccc}2&5/3&-1/3\\5&-8/3&1/3\\-2&1&0\end{array}\right]\left[\begin{array}{c}1\\6\\3\end{array}\right]$

$=\left[\begin{array}{c}7\\-10\\4\end{array}\right]$

thus the solutions is$(7,-10,4)$