<image>Figure 1 shows a rectangle with length 2m and width 2n, which is evenly divided into four smaller rectangles along the dotted lines using scissors. It is then rearranged into a square as shown in Figure 2.
(1) What do you think is the side length of the shaded square in Figure 2? ______ .
(2) Please find the area of the shaded part in Figure 2 using two different methods. Method 1: ______ Method 2: ______ .
(3) Can you write the equation that shows the relationship between the following three algebraic expressions by observing Figure 2? Expressions: (m+n)^{2}, (m-n)^{2}, mn. ______ .
(4) Based on the equivalence relationship in question (3), solve the following problem: If a-b=7 and ab=5, what is (a+b)^{2}? ______ .
(5) If a+b=-3 and ab=-28, what is a-b? ______ .
