rezolvaţi prin metoda reducerei

Răspuns:
[tex]\left \{ {{4x+9y=5} /*3\atop {3x-7y=-10}/*-4} \right.\\\\\\\left \{ {{12x+27y=15} \atop {-12+28y=40}} \right. \\\\\\55y=55= > y=55:55= > y=1\\\\4x+9=5= > 4x=5-9*1= > x=-4:4= > x=-1\\\\S= > x=-1;y=1[/tex]