ОДЗ: x >= 0
x -5√x +6 = 0
t = √x, t >= 0
t^2 -5t +6 = 0
D = 25 - 24 = 1
t = (5 -1) /2 = 2
t = (5 +1) /2 = 3
√x = 2
x = 4
√x = 3
x = 9
Ответ: 4, 9.
А
0 = -0.4*5 + 2
0 = -2 + 2
0 = 2
А - принадлежит
-0.4 = - 0.4 * 4 + 2
-0.4 = -1.6 + 2
-0.4 = 0.4
В - не принадлежит
<span>cos8x - cos2x = 0
-2sin5xsin3x=0
sin5xsin3x=0
sin5x=0 sin3x=0
5x=</span>πk 3x=πk; k∈Z
x=πk/5 x=πk/3;k∈Z