Why does the economy trade off inflation for unemployment in the short-run ?

Question

Why does the economy trade off inflation for unemployment in the short-run ?

Answer 1

inflation means excess of money supply in the system so by keeping salaries outgo lesser by resorting to unemployment the economic system willhave lesser of circulating money, so inflation will be reigned in.

Answer 2

The answer comes from Keynesian short-run macroeconomics. In the short-run the government can stimulate the aggregate demand through monetary or fiscal policy. More demand for goods and services makes firms hire to keep up with demand, which lowers unemployment.

But because the stimulus increases aggregate demand, thus shifting the aggregate demand curve, the overall price level in the economy rises. Which is what we call inflation.

To properly explain this you need to draw some graphs and also perhaps mention the Phillips curve which shows this relation.