由2X+Y+3Z=23得4X+2Y+6Z=46,式一;
由X+4Y+5Z=36得3X+12Y+15Z=108式二.
式一+式二=(4X+2Y+6Z)+(3X+12Y+15Z)=7X+14Y+21Z=7(X+2Y+3Z)=46+108=154;
得X+2Y+3Z=22.
由2X+Y+3Z=23得4X+2Y+6Z=46,式一;
由X+4Y+5Z=36得3X+12Y+15Z=108式二.
式一+式二=(4X+2Y+6Z)+(3X+12Y+15Z)=7X+14Y+21Z=7(X+2Y+3Z)=46+108=154;
得X+2Y+3Z=22.