discuss the keynession classical and non classical?

Answer 1

Here you go. Straight from wiki:

Keynesian economics promotes a mixed economy, where both the state and the private sector play an important role. Keynesian economics differs markedly from laissez-faire economics (economic theory based on the belief that markets and the private sector operate well on their own, without state intervention).

In Keynes's theory, general (macro-level) trends can overwhelm the micro-level behavior of individuals. Instead of the economic process being based on continuous improvement in potential output, as most classical economists had believed from the late 1700s on, Keynes asserted the importance of aggregate demand for goods as the driving factor of the economy, especially in periods of downturn. From this he argued that government policies could be used to promote demand at a macro level, to fight high unemployment and deflation of the sort seen during the 1930s.

Then....

In neoclassical economics, which combines Keynesian macro concepts with a micro foundation, the conditions of General equilibrium allow for price adjustment to achieve this goal.

More broadly, Keynes saw his as a general theory, in which utilization of resources could be high or low, whereas previous economics focused on the particular case of full utilization.