help!!!Maths about log

Solve the following equations for x.

1) (2x－3)/5+2 <=
x/2

10*[(2x－3)/5+2]<=10*(x/2)


2(2x－3)+20<=5x

4x－6+20<=5x

14<=x



2a ) 3^√x^2－1=2

3^√x^2=3

√x^2=1

｜x｜=1

x=+/-1





2b) 3^(√(x^2－1)=2

√(x^2－1)log3=log2

√(x^2－1)=log2/log3

x^2－1=(log2/log3)^2

x^2=1+(log2/log3)^2

x=+/-sqrt((1+(log2/log3)^2)




3)8^(x^2－2x)=1/2

2^(3x^2－6x)=2^(－1)

3x^2－6x=－1

3x^2－6x+1=0

x=(6+/-sqrt(36－12))/2=3+/-sqrt(6)



4) (1/5)^(2－x)=4

(2－x)log(1/5)=log4

(2－x)log(2/10)=2log2

(2－x)(log2－1)=2log2

2－x=2log2/(log2－1)

x-2=2log2/(1-log2)

x=2+2log2/(1－log2)=2/(1－log2)