Răspuns :
Notez cu x cati ani a trait, si cu y cati ani a domnit.
[tex] \left \{ {{y+1= \frac{2}{3}(x+1) } \atop {y-11= \frac{3}{5}(x-11) }} \right. \Leftrightarrow \left \{ {{3y+3=2x+2} \atop {5y-55=3x-33}} \right. \Leftrightarrow \left \{ {{3y-2x=-1} \atop {5y-3x=22}} \right. \Leftrightarrow \left \{ {{15y-10x=-5} \atop {15y-9x=66}} \right. \Leftrightarrow \\ \\ \Leftrightarrow \left \{ {{15y-9x=66} \atop {-x=-71}} \right. \Leftrightarrow \left \{ {{y= \frac{66+9x}{15} } \atop {x=71}} \right. \Leftrightarrow \left \{ {{y= \frac{66+9*71}{15} } \atop {x=71}} \right.[/tex]
[tex]\Leftrightarrow \left \{ {{y=47} \atop {x=71}} \right. .[/tex]
Stefan cel Mare a trait 71 de ani si a domnit 47 de ani.
[tex] \left \{ {{y+1= \frac{2}{3}(x+1) } \atop {y-11= \frac{3}{5}(x-11) }} \right. \Leftrightarrow \left \{ {{3y+3=2x+2} \atop {5y-55=3x-33}} \right. \Leftrightarrow \left \{ {{3y-2x=-1} \atop {5y-3x=22}} \right. \Leftrightarrow \left \{ {{15y-10x=-5} \atop {15y-9x=66}} \right. \Leftrightarrow \\ \\ \Leftrightarrow \left \{ {{15y-9x=66} \atop {-x=-71}} \right. \Leftrightarrow \left \{ {{y= \frac{66+9x}{15} } \atop {x=71}} \right. \Leftrightarrow \left \{ {{y= \frac{66+9*71}{15} } \atop {x=71}} \right.[/tex]
[tex]\Leftrightarrow \left \{ {{y=47} \atop {x=71}} \right. .[/tex]
Stefan cel Mare a trait 71 de ani si a domnit 47 de ani.