Такс.
12,15,18,21,24,27,30,33,36,39,42,45,48,51,54,57,60,63,66,69 и тд.
N=30
N(A)=6
P(A)=6/30=0,5
5.
1) log₁/₃ (1+log₃ (2ˣ -7))= -1
1+log₃ (2ˣ -7)=(¹/₃)⁻¹
log₃ (2ˣ -7)=3-1
2ˣ - 7=3²
2ˣ=9+7
2ˣ=16
x=4
Ответ: 4.
2) log₀.₅ (3+log₂ (3ˣ -7))= -2
3+log₂ (3ˣ -7)=(¹/₂)⁻²
3+log₂ (3ˣ -7)=2²
log₂ (3ˣ -7)=4-3
log₂ (3ˣ -7)=1
3ˣ - 7=2¹
3ˣ=2+7
3ˣ=9
x=2
Ответ: 2.
5^(n-2) =(5^n)/5²
3^(n+2) =3^n *3²
15^n =(5*3)^n =5^n *3^n
5^(n-2) *3^(n+2) =(5^n *3^n *3²) /5²
(5^n *3^n) : (5^n *3^n *3²)/5² =(5^n *3^n) * 5²/(5^n *3^n *3²) =5²/3² =25/9 =
2 7/9(две целых семь девятых)
a^n *b^n =(ab)^n
0.1х>=0.1+0.8
0.1х>=0.9
х>=0.9/0.1
х>=9