The points A, B, C and D all lie on the same line segment, in that order, such that the ratio of AB : BC: CD is equal to 1:4:1. If AD = 18, find
CD.

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

your answer should be 1/2 is less than or equal to x and 3/4 is greater than or equal to x

if you was gonna solve for a, a is a   < -12

parallelogram is the   answer