The triangle midsegment theorem states that if the midpoints of two sides of any triangle are joined by a line, then that line is parallel to the third side and its length is half of that third side.
With that statement, we can define that:
side AB = 0.5 (side XY)
x + 1 = 0.5 (5 x – 7)
x + 1 = 2.5 x – 3.5
1.5 x = 4.5
x = 3
Therefore, the length of side AX can now be calculated given x:
AX = 2 x – 2
AX = 2 * 3 – 2
AX = 4
Answer: AX = 4 units