(* #4, p. 338 *)
N[-Log[4]/Log[10]]

(* #9 *)
N[Log[10/3]]

(* #11 *)
N[(1-Log[2])/4]

(* #29 *)
Solve[Exp[x]==1,x]
Solve[Exp[x]==2,x]

(* #34 *)
Solve[x^2*10^x-x*10^x==2*10^x,x]

(* #37 *)
Solve[Log[x]==10,x]

(* #43 *)
Solve[4-Log[3-x,10]==3,x]

(* #59 *)
Plot[{Log[x],3-x},{x,.1, 10}]
Plot[{Log[x],3-x},{x,2, 2.4}]
Plot[{Log[x],3-x},{x,2.2, 2.22}]

(* #75 *)
Solve[5000*(1+.085/4)^(4*x)==10000,x]

(* #77 *)
Solve[5000*(1+.075/4)^(4*x)==8000,x]

(* #85 *)
Solve[Log[P/P0]==-h/k,P]
k=7
P0=100
Solve[Log[P/P0]==-h/k,P]
h=4
Solve[Log[P/P0]==-h/k,P]

(* #86 *)
Solve[Log[(T-20)/200]==-0.11t,T]
t=20
Solve[Log[(T-20)/200]==-0.11t,T]