Question

determine a solução do sistema

3x + y =10
2x + z =10
y + 2z =9

Answer 1

$2x+z=10 \\ 2x=10-z \\ x= \frac{10-z}{2} \\ \\ x= \frac{10-4}{2} \\ x= \frac{6}{2} \\x=3$

$3x+y=10 \\ 3.( \frac{10-z}{2})+y=10 \\ \frac{30-3z}{2} +y=10 \\ \\ 30-3z+2y=20 \\ 2y=3z-10 \\ y=\frac{3z-10}{2} \\ \\ y= \frac{3.4-10}{2} \\ \\ y=\frac{2}{2} \\ y=1$

$y+2z=9 \\ \\ \frac{3z-10}{2}+2z=9 \\ 3z-10+4z=18 \\ 7z=28 \\ z= \frac{28}{7} \\ z=4$