In a senate legislature, there were 119 more members in the house of representatives than in the senate. if there were m members in the senate, write an expression to represent the total members in the state legislature.

It is very important to go through the details given in the question. Based on those given details the answer to the question can be easily deduced.
The number of members in the senate = m
Then
The number of members in the House of Representatives = m + 119
So
The total number of members in the State Legislature = m + m + 119
                                                                                       = 2m + 119
From the above deduction we an conclude that there are 2m + 119 members in total in the state Legislature. I hope there is nothing complicated in the procedure for you to understand.