I cant see the image but just wanted to lyk u should use the mathaway app it gives you answers and an explanation instantly
So we're looking at two rectangles, one cut out of the other, so all you do is find the area of the big one, base times height equals area, minus the area of the small one, base times height equals area. So the equation you have to solve for is this,
Area=(12.6X14)-(3X8.4)
there are 6 faces multiply 25 by 6
25*6=150cm^2
7 is the range of this function
