three-pieceThe Solution.
Step 1:
We shall express each of the three pieces in terms of x.
First piece: x
Second piece: 2x
Third piece: 4x
Step 2:
We shall write the equation that defines the problem under consideration.

Step 3:
We shall obtain the lengths of the three piece of the board by substituting 7 for x as below.
he first piece: x = 7 inches
The second piece = 2x = 2x7 = 14 inches
The third piece = 4x = 4x7 = 28 inches.