Using the diagram below, what is the length of AC

9514 1404 393

  B.  4 mi  (the correct answer is marked)

Step-by-step explanation:

Corresponding sides are proportional:

  AC/EC = AB/ED

  AC = EC×AB/ED = (12 ft)×(7 mi)/(21 ft) = (84/21) mi

  AC = 4 mi

There is no need to convert from miles to feet, or vice versa, in this problem. The units of ft/ft cancel, so the resulting units associated with the numerical value are miles. (If the unwanted units don't cancel the proportion is written incorrectly.)

set each factor equal to 0

4x-3 = 0

2x-1 = 0

solve for x.

4x-3=0

4x=3

x= 3/4

solve for x. 

2x-1= 0

2x= 1

x= 1/2

eventually after a few more steps, your answer should be 1/2 is less than or equal to x and 3/4 is greater than or equal to x