Verified answer

3х+5у=14

2х-4у= -20       |:2

3х+5у=14

х-2у= -10

х=-10+2у

3*(-10+2у)+5у=14

-30+6у+5у=14

11у=14+30

11у=44

у=44:11

у=4

х=-10+2*4

х= -10+8

х= -2

Ответ:(-2;4)