14х + 2y = 86
2y = 86 - 14x
y = 43 - 7x
43 - 7x = - 2,5x
4,5x = 43
x = 430/45 = 85/9 = 9 4/9
y = - 2,5 • ( 85/9 ) = - ( 5/2 ) • ( 85/9 ) = - 425/18 = - 23 11/18
Ответ ( 9 4/9 ; - 23 11/18 )
15x+2(-2,5x)=86
15x-5x=86
10x=86
x=8,6
y=-2,5*8,6
y= -21,5
Ответ(8,6;-21,5)