<span>S=n(n+1)/2 </span>
<span>105=n(n+1)/2 </span>
<span>n^2+n-210=0 </span>
<span>n1=-15 (не удовл.) </span>
<span>n2=14 </span>
<span>14 отрезков => 15 точек</span>
((16x^2)^4)/(8x)^5=(8^4*2^4*x^8)/(8^4*8*x^5)=(2^4)/2^3*x^(8-5)=2x^3.
Log ₁/₃ ( x + y ) = 2
Log₃ ( x - y ) = 2
-------------------------
1/3 ^ 2 = x + y
3 ^ 2 = x - y
-------------------------
1/9 = x + y
9 = x - y
----------------------------
9 1/9 = 2x
x = 82/9 : 2
x = 82/18
x = 41/9
x = 4 5/9
------------------------------
y = x - 9
y = 4 5/9 - 8 9/9
y = - 4 4/9
Ответ ( 4 5/9 ; - 4 4/9 )
X²-30x+225⇒
x²-30x+225=0
a=1; b= -30; c=225;
D= b²-4ac = (-30)²-4·1·225 = 900-900 = 0
x =
=
= 15
Ответ: 15
:-)