Question

решите систему линейных урвнений {y-5x=-21 {3x+y-11=0

Answer 1

$left { {{y-5x=-21} atop {3x+y-11=0}} right. left { {{-5x+y=-21} atop {3x+y=11}} right. left { {{5x-y=21} atop {3x+y=11}} right. \8x=32\x=4\y=-21+5*4\y=-1$