For this case we have the following system of equations: [tex]2x + 3y + 2z = 26
-x + 7y-z = 21
3x + 2y-5z = 13[/tex] From equation 2 we can clear z: [tex]z = -x + 7y-21
[/tex] We substitute the values of z in equations 1 and 3: [tex]2x + 3y + 2 (-x + 7y-21) = 26
3x + 2y-5 (-x + 7y-21) = 13[/tex] From here, we obtain a system of two equations with two unknowns, whose graphical solution is given by the intersection of both lines: [tex]x = 5
y = 4[/tex] Note: See attached image for the graphic solution We now look for the value of z replacing the found values of the graphic solution: [tex]z = -x + 7y-21
z = -5 + 7 * (4) -21
z = 2[/tex] Therefore, the triple ordered solution is: [tex](x, y, z) = (5,4,2)
[/tex] Answer: [tex](x, y, z) = (5,4,2)
[/tex] See attached image
