3x+8y=20
5x+3y=23
x=23/5-3/5y
3(23/5-3/5y)+8y=20
69/5-9/5y+8y=20
69/5+31/5y=20 |•5
69+31y=100
31y=100-69
31y=31
y=1
x=23/5-3/5*1
x=20/5
x=4
ответ: (4;1)
3x+8y=20
5x+3y=23
3x+8y=20
x=23/5-3/5y
3(23/5-3/5y)+8y=20
69/5-9/5y+8y=20
69/5+31/5y=20 |•5
69+31y=100
31y=100-69
31y=31
y=1
x=23/5-3/5*1
x=20/5
x=4
ответ: (4;1)