2. сравнить:
а) (1/5)^0.2 =(1/5)^2/10 =(1/5)^1/5
(1/5)^1.2 =(1/5)^12/10 =(1/5)^6/5
1/5 >6/5, значит (1/5)^0.2 > (1/5)^1.2
б) 5^(-0.2) и. 5^(-1.2), тк x^-1 =1/x^1 тогда:
(1/5)^0.2 > (1/5)^1.2
3. уравнения:
а) 3^(x +1) =27^(x -1)
3^(x +1) =((3)^3)^(x -1)
3^(x +1) =3^(3(x -1)
3^(x +1) =3^(3x -3)
x +1 =3x -3
x -3x = -3 -1
-2x = -4
x =2
b) 1 =0.2^0, тогда:
x² +4x -5 =0
D =16 +20 =36 =6²
x1 =(-4 -6)/2 = -5
x2 =(-4 +6)/2 =1
ответ: x1 = -5; x2 =1