What do you thinh contributes to higher population density in
areas along the coasts of
Mexico?

density of 10 and over per square kilometer, while all the bo lands are less densely inhabited. Mexico, however, all three elements, rainfall, altitude, and relief, are favorable over broad areas; and the combination produces Mexico's densest population.

the perimeter of a triangle is 69 cm. side a is 5 cm shorter than side b. side c is twice as long as side a. find the length of each side. i need to know how to do it in 2 equations.  

equations:

a = b-5

c = 2a

a + b + c = 69