Fixing the issue in assumption of OLS step by step or one by one

Hi, I want to raise the issue related to know whether your OLS is ok or not. 

The **45-degree line** in economics and geometry refers to a line where the values on the x-axis and y-axis are equal at every point. It typically has a slope of 1, meaning that for every unit increase along the horizontal axis (x), there is an equal unit increase along the vertical axis (y). Here are a couple of contexts where the 45-degree line is significant:

The **hyperinflation in Hungary** in the aftermath of World War II (1945–1946) is considered the worst case of hyperinflation in recorded history. The reasons behind this extreme economic event are numerous, involving a combination of war-related devastation, political instability, massive fiscal imbalances, and mismanagement of monetary policy. Here's an in-depth look at the primary causes:

**Neutrality of money** is a concept in economics that suggests changes in the **money supply** only affect **nominal variables** (like prices, wages, and exchange rates) and have **no effect on real variables** (like real GDP, employment, or real consumption) in the **long run**.

Deflation in Japan, which has persisted over several decades since the early 1990s, is a complex economic phenomenon. It has been influenced by a combination of structural, demographic, monetary, and fiscal factors. Here are the key reasons why deflation occurred and persisted in Japan:

Hedging against inflation involves taking financial or investment actions designed to protect the purchasing power of money in the face of rising prices. Inflation erodes the value of currency over time, so investors seek assets or strategies that tend to increase in value or generate returns that outpace inflation. Below are several ways to hedge against inflation:

The **Phillips Curve** illustrates the relationship between inflation and unemployment, and how this relationship differs in the **short run** and the **long run**. Over time, economists have modified the original Phillips Curve framework to reflect more nuanced understandings of inflation and unemployment dynamics.

Dealing with inflation requires a combination of **fiscal and monetary policy** tools. Policymakers adjust these tools depending on the nature of inflation—whether it's **demand-pull** (inflation caused by excessive demand in the economy) or **cost-push** (inflation caused by rising production costs). Below are key approaches to controlling inflation through fiscal and monetary policy.