2cos²6x ≤1,5;
cos²6x ≤3/4;
|cos6x| ≤1/2*√3
- 1/2*√3≤ cos6x ≤1/2*√3 .
a) π/6 ≤ 6x ≤ π -π/6 ;
π/6 ≤6x ≤5π/6 ;
2π*k +π/6 ≤6x ≤5π/6+ 2π*k ;
π/3*k +π/36 ≤ x≤ 5π/36 +π/3*k , k∈Z
b) π+π/6 ≤ 6x ≤ 2π -π/6 ;'
7π/6 ≤ 6x ≤ 11π/6 ;
2π*k + 7π/6 ≤ 6x ≤ 11π/6 + 2π*k ;
π/3*k + 7π/36 ≤ x ≤ 11π/36 + π/3*k ;
=================================x========
x ∈[ π/3*k +π/36 ; 5π/36 +π/3*k ] U [π/3*k + 7π/36 ;11π/36 + π/3*k ] k∈Z
5) -4; 4. 0; -2/3
6) -4; 4.-7; 7
3(х-3)=4(х-4)
3х-9=4х-16
4х-3х=16-9
х=7
№ 1.
1)5а + 5b = 5(a + b)
2)7a - 7b = 7(a - b)
3)2.5x - 2.5y = 2.5(x - y)
4)1/3x + 1/3y = 1/3(x + y)
№ 2
1)16x - 8 = 8(2x - 1)
2)24a + 6 = 6(4a + 1)
3)18b + 9 = 9(2b + 1)
4)25c - 5 = 5(5c - 1)
5)16c - 24d = 8(2c - 3d)
6)21m + 28n = 7(3m + 4n)
№ 3
1)ab + a = a(b + 1)
2)mn - m = m(n - 1)
3)a^3b - b = b(a^3 - 1)
4)x^3y + y = y(x^3 + 1)
5)a^3b^3 - b = b(a^3b^2 - 1)
6)x^3y^2 + y = y(x^3y + 1)
7)a^3b^2 + b^2 = b^2(a^3 + 1)
8)x^3y^2 - y^2 = y^2(x^3 - 1)
9)a^3b^2 - ab^2 = ab^2(a^2 - 1)
10)x^3y^2 + xy^2 = xy^2(x^2 + 1)
№ 4
1)2ab - 4a = 2a(b - 2)
2)3xy + 6x = 3x(y + 2)
3)5mn^2 + 10m = 5m(n^2 + 2)
4)3x^2y - 15x^2 = 3x^2(y - 5)
5)27y^4 - 18y^2 = 9y^2(3y^2 - 2)
6)42p^3 + 14p^2 = 14p^2(3p + 1)