What’s the answer to this?

P would then equal (-4,7) after the reflection

Don’t let R confuse you as it stands for Reflection. In this question you want to do a reflection across the y-axis.

The formula for reflection across the y-axis is (-x,y). In meaning as you cross the y-axis you y-value will always stay the same while your x-value with the opposite of what it is currently.

With that being said you want to plug in your values from point P to the formula which will leave you with (-4,7)