масса кошки x
масса щенка y
\left \{ {{x=11-\frac{3}{2}y} \atop {2y+3x=23}} \right.=> \left \{ {{x=11-\frac{3}{2}y} \atop {2y+3*(11-\frac{3}{2}y)=23}} \right.=>\\ \left \{ {{x=11-\frac{3}{2}y} \atop {2y+33-\frac{9}{2}y=23}} \right.=> \left \{ {{x=11-\frac{3}{2}y} \atop {-\frac{5}{2}y=-10}} \right.+> \left \{ {{x=11-\frac{3}{2}y} \atop {y=4}} \right.=>\\ \left \{ {{x=11-\frac{3}{2}*4} \atop {y=4}} \right.=> \left \{ {{x=11-6} \atop {y=4}} \right.=> \left \{ {{x=5} \atop {y=4}} \right." alt="\left \{ {{3y+2x=22} \atop {2y+3x=23}} \right. => \left \{ {{x=11-\frac{3}{2}y} \atop {2y+3x=23}} \right.=> \left \{ {{x=11-\frac{3}{2}y} \atop {2y+3*(11-\frac{3}{2}y)=23}} \right.=>\\ \left \{ {{x=11-\frac{3}{2}y} \atop {2y+33-\frac{9}{2}y=23}} \right.=> \left \{ {{x=11-\frac{3}{2}y} \atop {-\frac{5}{2}y=-10}} \right.+> \left \{ {{x=11-\frac{3}{2}y} \atop {y=4}} \right.=>\\ \left \{ {{x=11-\frac{3}{2}*4} \atop {y=4}} \right.=> \left \{ {{x=11-6} \atop {y=4}} \right.=> \left \{ {{x=5} \atop {y=4}} \right." align="absmiddle" class="latex-formula">
масса кошки - 5 кг
масса щенка - 4 кг