The sum of three numbers is 131. the second of three numbers is seven more than twice the first. the third number is 12 less than the first. what equation can be used to solve the problem?

The angle of a triangle are given as 6x,(x-3), and (3x+7). find x then find the measures of the angles

Math it's appreciated. (picture provided)

Here is my question! jayne is studying urban planning and finds that her town is decreasing in population by 3% each year. the population of her town is changing by a constant rate. true or false?