{ x -8y -17 =0
{3x+4y -23 = 0 |*2
{ x -8y = 17
{ 6x +8y = 46
x -8y +6x+8y = 17+46
7x = 63
x= 63/7
x= 9
9 - 8y = 17
-8y = 17-9
-8y= 8
y= 8 /(-8)
y= -1
ответ : ( 9 ; -1)
{15x + 11y - 47 = 0
{ 5x - y + 17 = 0 |*11
{ 15x + 11y = 47
{ 55x - 11y = -187
15x + 11y + 55x - 11y = 47 + (-187)
70x = -140
x= -140/70
x = -2
15*(-2) + 11y = 47
-30 +11y = 47
11y = 47+30
11y=77
y= 77/11
y= 7
ответ : ( - 2 ; 7)