Question

ХIf B is the midpoint of AC, AB= 3x-1 and AC = 8x – 20,find BC.

Answer 1

B is the midpoint of AC.

Then AB=BC and AB + BC=AC.

Then we can write:

$\begin{gathered} AB+BC=AC \\ (3x-1)+(3x-1)=8x-20 \\ 6x-2=8x-20 \\ -2+20=8x-6x \\ 2x=18 \\ x=\frac{18}{2} \\ x=9 \end{gathered}$

Then BC is:

$BC=3x-1=3\cdot9-1=27-1=26$

Answer: BC = 26