The opposite vertex to (-5, -7) is (-1, 3).
The perimeter is given as 28 units, so we have the equation:
2a + 2b = 28
Solving for (a) we get:
a = 14 - b
Now, the area is given as 48 square units:
A = ab = (14 - b)b = 48
Solving for (b), we get two possible solutions: (b = 4) or (b = 10).
If (b = 4), then (a = 14 - b = 10).
If (b = 10), then (a = 14 - b = 4).
So, we have two possible rectangles:
1. Dimensions: (a = 10), (b = 4)
2. Dimensions: (a = 4), (b = 10)
Now, let's check which one satisfies the condition that (-5, -7) is one vertex and the origin is in the interior of the rectangle.
For the point (-5, -7):
1. If (a = 10) and (b = 4), the opposite vertex is (-5 + 10, -7 + 4) = (5, -3)
2. If (a = 4) and (b = 10), the opposite vertex is (-5 + 4, -7 + 10) = (-1, 3)
The rectangle with dimensions (a = 4) and (b = 10) satisfies the condition.
Therefore, the opposite vertex to (-5, -7) is (-1, 3).