Question

Помогите решить уравнение,пж.Даю 23б
x+y=180
x-y=130

Answer 1

$left { {{x+y=180} atop {x-y=130}} right. \ left { {{x=180-y} atop {180-y-y=130}} right. \ left { {{x=180-y} atop {180-2y=130}} right. \ left { {{x=180-y} atop {-2y=130-180}} right. \ left { {{x=180-y} atop {-2y=-50}} right. \ left { {{x=180-y} atop {y=25}} right. \ left { {{x=180-25} atop {y=25}} right. \ left { {{x=155} atop {y=25}} right.$