Question

IF AB = (2x + 23). BC = (12 + 7x), and CD = 19 - 9x), find AD.

Answer 1

The addition of length of each line segment gives the value of AD.

$\begin{gathered} \text{From the number line, AB+BC+CD=AD} \\ AD=(2x+23)+(12+7x)+(19-9x)=2x+7x-9x+23+12+19=54 \end{gathered}$

The value of AD is 54.