Let's clarify and solve the equation step by step. Starting from the equation we derived:
\[
0.20x = 80
\]
To isolate \( x \), we'll divide both sides of the equation by 0.20:
\[
x = \frac{80}{0.20}
\]
Now we can calculate:
\[
x = \frac{80}{0.20} = 80 \div 0.20 = 80 \times 5 = 400
\]
So, your grade \( x \) is 400 points.
Now, you had the rearrangement .20 = 80x, which is incorrect. The correct steps lead to:
- Start with \( 0.20x = 80 \).
- Divide both sides by \( 0.20 \).
- Solve for \( x \).
The solution we found indicates that your grade is 400 points. If you have any further questions or if something isn't clear, feel free to ask!