Match the simplified expressions to an equivalent expression

News cameras take an overhead picture of a crowd at an outdoor event journalist then count the total number of people in the picture and use the sample of estimate the total number of people in the crowd this process is an example of

One line passes through (-7,-4) and (5,4) . another line passes through the point (-4,6) and (6,-9)

Three times the sum of a number and seven is negative thirty-six. what is the number?