Question

y=x-1 5x+2y=16

Answer 1

5x+2y=16;

x+y=16-5-2;

x+y=9;

x+x-1=9;

x+x=9+1;

2x=10;

x=10:2;

x=5.

Ответ: 5.

Answer 2

y=x-1

5x+2y=16

 

5x+2(x-1)=16

5x+2x-2=16

7x=18

x=18/7 (2.5)

 

проверка

x=y+1

5(y+1)+2y=16

5y+5+2y=16

7y=11

y=11/7 (1.5)