Question

решите системы уравнений :
а)х+у=7 б) 2х-у=3
5х-3у=11 3х-у=5

Answer 1

$left { {{x+y=7} atop {5x-3y=11}} right. left { {{x=7-y} atop {5(7-y)-3y=11}} right. left { {{x=7-y} atop {y=3}} right. left { {{x=4} atop {y=3}} right.$
$5(7-y)-3y=11$
$35-5y-3y=11$
$8y=24$
$y=3$
$left { {{2x-y=3} atop {3x-y=5}} right. left { {{y=2x-3} atop {y=3x-5}} right. left { {{3x-5=2x-3} atop {y=3x-5}} right. left { {{x=8} atop {y=19}} right.$
$3x-5=2x-3$
$x=8$

Answer 2

не за что

Answer 3

точно

Answer 4

ща исправлю