Answer:
AC = 23
BD = 23
Explanation:
ABCD is a rectangle,
AC and BD are its diagonals.
Diagonals of a rectangle are congruent.
Therefore,
AC = BD
7x - 40 = 2x + 5
7x - 2x = 5 + 40
5x = 45
x = 45/5
x = 9
BD = 2x + 5 = 2*9 + 5 = 18 + 5 = 23
AC = 7x - 40 = 7*9 - 40 = 63 - 40 = 23