Add small code example for drawing a flipped texture

Frequently-asked-Questions--Common-Questions.md

@@ -97,9 +97,17 @@ DrawText(text, textStartX, textStartY, fontSize, LIGHTGRAY);
 Drawing a texture flipped requires the use of either `DrawTextureRec`, or `DrawTexturePro` functions.
 Every single texture drawing function calls `DrawTexturePro` to do its work, but only these two expose the parameters necessary to flip a texture (the source rectangle).
 
-To flip the texture, simply pass a source rectangle with a negative width and height.
+To flip the texture, simply pass a source rectangle with a negative width or height.
+
+```c
+Rectangle source = (Rectangle) { 0, 0, -texture.width, texture.height };
+
+DrawTextureRec(texture, source, (Vector2) { 0, 0 }, WHITE);
+```
+
+The above code will draw a texture flipped in the X axis.
 
 # Why is my render texture upside down?
 
-All textures in OpenGL by default have the origin in the lower-left corner. When you load a normal texture, raylib flips the image data for you, however this cannot be done with a render texture.
-The solution is to flip your texture when drawing, see the above paragraph for how to do this.
+All textures in OpenGL by default have the origin in the lower-left corner, while the screen origin is in the upper left. When you load a normal texture, raylib flips the image data for you, however this cannot be done with a render texture.
+The solution is to flip your texture vertically when drawing, see the above paragraph for how to do this.