rozwiąż równanie x=3y - 69 12x-7y=-16 y=-2x-1 x=y+7

1). {x=3y-69 {12x-7y= -16 {x=3y-69 {12·(3y-69)-7y= -16 {x=3y-69 {36y-828-7y= -16 {x=3y-69 {29y= -16+828 {x=3y-69 {29y=812 /:29 {x=3y-69 {y=28 {x=3·28-69 {y=28 {x=15 {y=28 2). {y= -2x-1 {x=y+7 {y= -2x-1 {x= -2x-1+7 {y= -2x-1 {x+2x=6 {y= -2x-1 {3x=6/:3 {y= -2x-1 {x=2 {y= -2·2-1 {x=2 {y= -4-1 {x=2 {x=2 {y= -5