Ответ: 
Объяснение:
\left \{ {{x=1} \atop {x+y=8}} \right. => \left \{ {{x=1} \atop {(1)+y=8}} \right. =>\left \{ {{x=1} \atop {y-7=0}} \right. => \left \{ {{x=1} \atop {y=7}} \right." alt="\left \{ {{2x=2|:2} \atop {x+y=8}} \right. => \left \{ {{x=1} \atop {x+y=8}} \right. => \left \{ {{x=1} \atop {(1)+y=8}} \right. =>\left \{ {{x=1} \atop {y-7=0}} \right. => \left \{ {{x=1} \atop {y=7}} \right." align="absmiddle" class="latex-formula">
