\left \{ {{2^{y-1}=(2^2)^{0,5x}} \atop {7x+y=3^2}} \right. <=> \left \{ {{2^{y-1}=2^x} \atop {7x+y=9}} \right. \\\
\left \{ {{y-1=x} \atop {7x+y=9}} \right. <=> \left \{ {{y=x+1} \atop {7x+x+1=9}} \right. <=> \left \{ {{y=x+1} \atop {8x=8}} \right.\\\
\left \{ {{y=x+1} \atop {x=1}} \right.<=> \left \{ {{y=2} \atop {x=1}} \right." alt=" \left \{ {{2^{y-1}=4^{0,5x}} \atop {log_3(7x+y)=2}} \right. <=> \left \{ {{2^{y-1}=(2^2)^{0,5x}} \atop {7x+y=3^2}} \right. <=> \left \{ {{2^{y-1}=2^x} \atop {7x+y=9}} \right. \\\
\left \{ {{y-1=x} \atop {7x+y=9}} \right. <=> \left \{ {{y=x+1} \atop {7x+x+1=9}} \right. <=> \left \{ {{y=x+1} \atop {8x=8}} \right.\\\
\left \{ {{y=x+1} \atop {x=1}} \right.<=> \left \{ {{y=2} \atop {x=1}} \right." align="absmiddle" class="latex-formula">