[tex] \left \{ {{39x-8y=99} \atop {52x-15y=80}} \right. [/tex]
[tex] \left \{ {{ y=\frac{39x-99}{8} } \atop {52x-15*\frac{39x-99}{8}=80}} \right. [/tex]
[tex]52x-15*\frac{39x-99}{8}=80 [/tex]
[tex]52x-\frac{585x+1485}{8}=80[/tex]
[tex] \frac{52x*8}{8}-\frac{585x+1485}{8}= \frac{80*8}{8} [/tex]
Ahora quitamos los denominadores:
[tex]{416x}-{585x+1485}={640} [/tex]
[tex]-169x=640-1485[/tex]
[tex]-169x=-845[/tex]
[tex]x = \frac{-845}{-169} [/tex]
[tex]x = 5[/tex]
Sustituimos la ``x´´ en la primera ecuacion:
[tex]39*5-8y=99 [/tex]
[tex]195-8y=99[/tex]
[tex]8y = 195-99[/tex]
[tex]y = \frac{96}{8} [/tex]
[tex]y = 12[/tex]
Solución:
X = 5 ; Y = 12
espero haberte sido de ayuda
salu2!!