How are public attitudes toward federalism changing?

For much of its history, the United States had a notably decentralized government structure. Since the 1930s, the national government has undertaken new efforts to regulate the economy and society and to redistribute resources. Those new efforts have implied a greater centralization of authority in Washington. In the past the public often supported such centralization. Public opinion about federalism has changed. Voters are more supportive of decentralized policymaking on many issues where they previously supported a stronger national role. This shift in the public mood is consistent with other polling data that indicates profound distrust in the capacity of the federal government to act on behalf of the public good. On some issues, like national defense, much of the public continues to support national primacy. Such issues are often assigned to Washington by the Constitution. In contrast, much polling finds that many citizens believe state and local governments are likely to perform better than Washington. Americans support a more decentralized federalism than in the past both on particular issues and as a general matter of institutional confidence.

Explanation:

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