Answer
$x = 1$
Work Step by Step
The diagonals of a parallelogram bisect one another. According to theorem 6-18, the diagonals of a rectangle are congruent; therefore, the two segments shown are congruent to one another. Let's set the two expressions equal to one another:
$8x + 3 = 4x + 7$
Subtract $4x$ from each side of the equation to move variables to the left side of the equation:
$4x + 3 = 7$
Subtract $3$ from each side of the equation to move constants to the right side of the equation:
$4x = 4$
Divide both sides by $4$ to solve for $x$:
$x = 1$
