Question

(1,2x-3,4y=12
(2,5x+1,4y=25

Answer 1

$\displaystyle\bf\\\left \{ {{1,2x-3,4y=12} \atop {2,5x+1,4y=25}} \right. \\\\\\\left \{ {{0,6x-1,7y=6} \ |\cdot(-5) \atop {0,5x+0,28y=5} \ |\cdot 6} \right. \\\\\\+\left \{ {{-3x+8,5y=-30} \atop {3x+1,68y=30}} \right. \\------------\\10,18y=0\\\\y=0\\\\0,6x=6+1,7y=6+1,7\cdot 0=6\\\\x=6:0,6=10\\\\Otvet \ : \ (10 \ , \ 0)$