How to do unit conversions​

Aphoto of a painting measured 13 x 17 inches the scale of the photo to the original painting is 1 inch to 3 inches. what is the size of this painting

Find the missing factor. 7s2 + 25s + 12 = (s + 3)( ).

Me! 50 points! why does when we come home, our door is unlocked and there is grease on the door knob, me solve this , and i don't know what category this goes under