Chapter 10 - Section 10.2 - Systems of Linear Equations in Several Variables - 10.2 Exercises - Page 697: 7

X=1 Y=3 Z=2

$x-2y+4z=3$ $y+2z=7$ $z=2$ Call $x-2y+4z=3$ Equation 1 Call $y+2z=7$ Equation 2 Call $z=2$ Equation 3 Substitute Equation 3 (z=2) in Equation 2. $y+2(2)=7$ $y+4=7$ $y=7-4$ $y=3$ Now you have solution of Y and Z so, substitute in Equation 1 $x-2(3)+4(2)=3$ $x-6+8=3$ $x+2=3$ $x=3-2$ x=1