Let $x$ represent the original price. How can you write an equation that says that the sale price, $45, is a certain percentage of $x$?

Remember that 75% can be written as $0.75$ or $\tfrac{3}{4}$. Use one of these forms to write and solve the equation relating $x$ and $45.

Once you have an equation like $0.75x = 45$, isolate $x$ by doing the same operation to both sides, then compute the final value.

In a new expression line, type 45/0.75 and press Enter. The value that Desmos outputs is the original price of the jacket before the 25% discount.

A 25% discount means the customer is paying the remaining 75% of the original price (because $100\% - 25\% = 75\%$). So the sale price, $45, is 75% of the original price.

Let $x$ be the original price of the jacket.

Since the sale price is 75% of the original price, we can write:

Here, $0.75$ is the decimal form of 75%.

To isolate $x$, divide both sides of the equation $0.75x = 45$ by $0.75$:

Now you just need to compute this division.

Calculate $\frac{45}{0.75}$.

One way is to rewrite $0.75$ as $\tfrac{3}{4}$:

So the original price of the jacket was $60.