Answer:
AB = 3
Step-by-step explanation:
Since AB is a perpendicular bisector then Δ is isosceles and AD = AC, that is
4x - 1 = 2x + 3 ( subtract 2x from both sides )
2x - 1 = 3 ( add 1 to both sides )
2x = 4 ( divide both sides by 2 )
x = 2
Hence AB = x + 1 = 2 + 1 = 3
