1) 4x^2≤25
4x^2 - 25 ≤0
(2х-5)×(2х+5) ≤ 0
Cos2x ≥ √2/2
-pi/4+2pi*n≤2x≤pi/4+2pi*n
-pi/8+pi*n≤x≤pi/8+pi*n≤
[-pi/8+pi*n;pi/8+pi*n]
(3m+n)^2=(9/7+4/7)^2=169/49
2)(8x-3)^2=0
8x-3=0
8x=3
x=3/8
3)a)3x(3x+4)+(2-y)(2+y)
б)(3x-2-x-1)(3x-2+x+1)=(2x-3)(4x-1)
в)m^5(m^3+3^3)