cos(x) = 0
x + 2*y = 7
x + 2*y = 7
-4.71238898038469
5.85619449019234
-1.57079632679490
4.28539816339745
x1 = -10.99557428756428 y1 = 8.997787143782138
x2 = 10.99557428756428 y2 = -1.997787143782138
x3 = -1.570796326794897 y3 = 4.285398163397448
x4 = 1.570796326794897 y4 = 2.714601836602552
x4 = 1.570796326794897 y4 = 2.714601836602552