Answer:
MK = 23
Step-by-step explanation:
Rectangle means that the angles are all 90 degrees, so all the sides are not tilted in any direction. Meaning the JL = MK, therefore:
2x + 5 = 7x - 40
subtract 5 from both sides
2x = 7x - 45
subtract 7x from both sides
-5x = -45
divide by -5
x = 9
Now input 9 into the equation
MK = 7(9) - 40 = 63 - 40 = 23