Question

x+2y-3=0
x-y+z=1
3x+y+2z=5
resolva os determinantes

Answer 1

$X+2y-3=0 \\x=3-2y \\ \\x-y+z=1 \\z=1-x+y \\z=1-(3-2y)+y \\z=1-3+2y+y \\z=-2+3y \\ \\3x+y+2z=5 \\3*(3-2y)+y+2*(-2+3y)=5 \\9-6y+y-4+6y=5 \\y=5-9+4 \\y=0 \\ \\z=-2+3y \\z=-2+3*0 \\z=-2 \\ \\x=3-2y \\x=3-2*0 \\x=3$