Raphael paid $160 for a camera during a 75% off sale. what was the camera's regular price?

Basically, Raphael bought the camera at 25% of the original price.

One simple trick here is that 25% is one third of 75%. So all you need to do is MULTIPLY $160 by 4 to get how much the camera's regular price was.

160 x 4 = 640

The camera's regular price was $640.00

0,(x-3)^2=0.x=3 this is the only root