If you want to learn basic economics, I will try to discuss some here:
TOPIC 1: Budget Constraints
Let
P
1= Price of commodity 1
P
2= Price of commodity 2
x
1= Number of units of commodity 1
x
2= Number of units of commodity 2
m = your income/budget
Let us assume you have a consumption bundle containing x
1 units of commodity 1 and x
2 units of commodity 2 having P
1 and P
2 the prices of commodity 1 and 2, respectively, and you have an income/budget amounting to m.
Q1: When is the consumption bundle affordable to you?
The consumption bundle is affordable if the total price of having commodity 1 and commodity 2 is less than or equal to your income, or P
1x
1 + P
2x
2 = m.
You can graph the equation P
1x
1 + P
2x
2 = m:
Anything within the budget line are the consumption bundles that you can afford while anything beyond the budget line are the consumption bundles that you cannot afford.
Reference: Varian (2014). Intermediate Microeconomics: A Modern Approach (Ninth Edition)
FOR DISCUSSION (give your answer in the comments):
a. How do the budget set and budget constraint change as income, m, increases?
b. How do the budget set and budget constraint change as income, m, decreases?
c. How do the budget set and budget constraint change as the price of commodity 1, P
1, decreases?