## Geometry: Common Core (15th Edition)

$x = 4$
In a rectangle, diagonals are congruent and bisect one another; therefore, we can set the two bisected segments equal to one another: $2x - 1 = x + 3$ Add $1$ to each side of the equation to move constants to the right side of the equation: $2x = x + 4$ Subtract $x$ from each side of the equation to move variables to the left side of the equation: $x = 4$