1 2/3*2 1/5=5/3*11/5=11/3=3 2/3
Складываем почленно
х²+х²+у²+(-у²)=5+3
2х²=8
х²=4
х=2 и х=-2
Решение
1) 4sin130° / [sin65° * sin25°] =
= [4*sin(180° - 50°)] / [1/2 * (cos(65° - 25) - cos(65° + 25°)] =
= 8*sin50° / [cos40° - cos90°] = [8*sin(90° - 40°)] / cos40° =
= 8*cos40° / cos40° = 8
2х-5-(х-1)=-5(-1-х)-5
2x-5-x+1-5-5x+5 = 0
4x = -4
x= -1