log√₇2* log ₄ 5* log ₁₂₅ 49=      

log₇4 *  log ₄ 5* log( ₅³) 7² = 1/(log ₄7) * log ₄ 5 * (2/3)* log ₅7 =

= log₇ 5 * (2/3)* log ₅7 = 2/3

к сведению log₇ 5* log ₅7 =1