Question

решить систему :
{5х=92-8у
{5у=92-6х

Answer 1

$\left \{ {{5x=92-8y} \atop {5y=92-6x}} \right. \\ \\ \left \{ {{5x+8y=92} \atop {6x+5y=92}} \right.$
Умножим первое уравнение на 6, второе на (-5) и сложим
$\left \{ {{30x+48y=552} \atop {-30x-25y=-460}} \right.$
23у=92
у=4
5х=92-8у
5х=92-32
5х=60
х=12
ответ. х=12  у=4

Answer 2

5x+8y=92(5)        25x+40y=460         25x+40y-40y-48x=460-736

5y+6x=92(-8)       -40y-48x=-736        -23x=-276

                                                             x=-276:(-23)

                                                              x=12

                                                              5*(умножаем)12+8y=92

                                                              8y=92-60

                                                              8y=32

                                                              y=32:8

                                                               y=4

                                                                (12;4)