Question

Stiind ca lg 7 p si lg 5=q, sa se exprime in functie de p si q
a) lg 0,7 b) lg 3 radical 7 c) lg 35 d) lg 175 e) lg 7 radical 5

Answer 1

lg 0.7 = lg ( 7/10 ) = lg 7 - lg 10 = lg 7 - 1 = p-1

lg 35 = lg ( 7*5 ) = lg7 +lg5 = p+q

lg 175 = lg ( 7*5*5 ) = lg 7 + 2lg5 = p + 2q