Why is it useful for historians to base certain studies on the analysis of historical themes

Write two paragraphs to explain how the cold war changed after the 1960s. first, identify the ways it changed during leonid brezhnev's leadership in the 1970s. then, explain how the cold war changed when ronald reagan was in office in the early 1980s. include supporting facts and details from the text in your response.

What affected the second industrial revolution have on transportation

If f(x) = 3x + 2 and g(x) = 2x - 2. what is (f - g)(x)?