1) (x, y) = (3, 1)
{3x-2y=7
{2x+2y=8
{3x-2y=7
{2y=8-2x
3x-(8-2x)=7
x=3
2y=8-2*3
y=1
(x, y) = (3, 1)
{3*3-2*1=7
{2*3+2*1=8
{7=7
{8=8
(x, y) = (3, 1)
2) (x, y) = (-25/3, - 325/3)
{7х-0,4у=-15
{4х-0,4у=10
{7х-0,4у=-15
{-0,4y=10-4x
7x+10-4x=-15
x=-25/3
-0,4y=10-4*(-25/3)
y=-325/3
(x, y) = (-25/3, - 325/3)
{7*(-25/3)-0,4*(-325/3)=-15
{4*(25/3)-0,4*(-325/3)=10
{-15=-15
{10=10
(x, y) = (-25/3, - 325/3)
3) (x, y) = (-38, - 920/30)
{5х-0,6у=-6
{2х-0,3у=16
{5х-0,6у=-6
{x=8+3y/20
5(8+3y/20)-0,6y=-6
y=-920/3
(x, y) = (-38, - 920/30)
{5*(-38)-0,6*(-920/3)=-6
{2*(-38)-0,3*(-920/3)=16
{-6=-6
{16=16
(x, y) = (-38, - 920/30)
0 + πк меньше πх/2 ≤ π/2 + πк | : π/2, где к ∈Z
2 к меньше х ≤ 1 + 2к, где к ∈Z