Salma, felipe, and eric sent a total of 82 text messages during the weekend. felipe sent 7 more messages than salma. eric sent 3 times as many messages as salma. how many messages did they each send?

Eric and Felipe's messages are described in terms of Salmas's, so:

Salma's = x                     3x+x+x+7=82
Eric's = 3x                               5x+7=82
Felipe's = x+7                              5x=75
                                                      x=15
Salma wrote 15 messages, Eric wrote 45, and Felipe wrote 22.  15+45+22=82 

Multiply 9 and 67. then multiply 3 with 67. lastly the answer that you got for 9x67 is to be subtracted by the answer you got for 3x67

If gravity is one third on mars then weight also one third on mars