2)log12(27)=a;log6(16)=?
log12(3^3)=3•log3(3)/log3(12)=3/(log3(3)+2log3(2))=3/(1+2log3(2))=a
3=a+2alog3(2)
log3(2)=(3-a)/2a
log6(16)=4log6(2)=4•log3(2)/log3(6)=
4log3(2)/(1+log3(2))=4(3-a)/2a:(1+(3-a)/2a)=
2(3-a)/a:(a+3)/2a=2(3-a)/a*2a/a+3=
4(3-a)/(3+a)
3)a)log30(x)=1/logx(30)=
1/(logx(5)+logx(2)+logx(3))
b)1/(log2(x)•log3(x)•log5(x))
*1/(logx(5)+logx(2)+logx(3))=
log2(x)•log3(x)+log3(x)•
log5(x)+log5(x)•log2(x)
c)(log2(x)•log3(x)+log3(x)•
log5(x)+log5(x)•log2(x)):
(log2(x)•log3(x)+log3(x)•
log5(x)+log5(x)•log2(x))
=1
Y=√4-2x
Область определения: 4-2х≥0
-2х≥-4
х≤2
6x^2+1>5x-x^2/4
24x^2+4>20x-x^2
25x^2-20x+4>0
x= (10+- sqrt(100-100))/25= 0,4.
Ответ: x<0,4.
<span>у=3х+18
а)
х=-2.5
у=-7.5+18
у=10.5
б)
у=-3
-3=3х+18
3х=-21
х=-7
в)
А(-5,3)
х=-5
у=3
3=3*(-5)+18
3=-15+18
3=3 Верно
Значит,проходит через точку А.
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