How did the land act of 1820 change regulations regarding western settlement?

The Land Act of 1820 established the ban on purchasing any of the United States' public domains in an installment or credit form of payment over four years. It actually just lowered the prices per acre but ended the credit or installment purchases.

How the Land Act of 1820 made changes to the rules about western settlement is that, it decreased the per acre price but ended in purchases in credit. This act has been enacted on the year 1820 by the United States federal law wherein the lowered payments are paid in an installment basis.

Not sure this is a hard one huh