(i) Given,
⇒ a = log10x
⇒ x = 10a.
Hence, x = 10a.
(ii) Given,
⇒log105x2⇒log10(x2)51⇒51 log10(x2)⇒51×2log10x⇒51×2log1010a⇒52alog1010⇒52a×1⇒52a.
Hence, log105x2=52a.
(iii) Given,
⇒ log103x
⇒ log103 + log10x
⇒ log103 + log1010a
⇒ log103 + alog1010
⇒ log103 + a.
Hence, log103x = log103 + a.