при каком значении f(x) графики функций у=f(х) и  у= модуль f(x)модуль  совпадают?

Write the verbs in correct tense form. Use the rule of the sequence of tenses.

Tom said that it (take) ___ him an hour to get to the station

She ased them if the (play) ___ tennis later in the affternoon.

Mary asked her brother if he (can) ___ tell her the way to the shop

 The told us the (visit) ____ the Tretyakovkay gallery the next sunday. 

Jack said that he ___ already ___ (write) the latter.

За ранее спасибо!

Подскажите пожалуйсто какое значение выполняет сердцевина?