7)
Let, width = y
Area = Length * width
12 13/16 = 3 3/4 * y
205/16 = 15/4 * y
205(4) = 15(16)*y
820 = 240y
y = 820/240
y = 41/12
or
width = 3 5/12 - (ans)
8) area of square = length * length
length = 7 3/5 or 38/5
area of square = 38/5 * 38/5 = 1444/25 or 57 19/25 - (ans)
9) -(-3/5)^3
-(-27/125)
- * - = +
so 27/125 - (ans)