Question

2x-3y+z=1
4x-5y+2=-3
5x-7y+3z=2
метод Крамера ,помогите пожалуйста

Answer 1

$\Delta =\left|\begin{array}{ccc}2&-3&1\\4&-5&2\\5&-7&3\end{array}\right|=2(-15+14)+3(12-10)+(-28+25)=1\\\\\\\Delta _{x}=\left|\begin{array}{ccc}1&-3&1\\-3&-5&2\\2&-7&3\end{array}\right|=(-15+14)+3(-9-4)+(21+10)=-9$

$\Delta _{y}=\left|\begin{array}{ccc}2&1&1\\4&-3&2\\5&2&3\end{array}\right|=2(-9-4)-(12-10)+(8+15)=-5\\\\\\\Delta _{z}=\left|\begin{array}{ccc}2&-3&1\\4&-5&-3\\5&-7&2\end{array}\right|=2(-10-21)+3(8+15)+(-28+25)=4\\\\\\x=\frac{\Delta _{x}}{\Delta }=-9,\; \; y=\frac{\Delta _{y}}{\Delta }=-5\; ,\; \; z=\frac{\Delta _{z}}{\Delta }=4$