Geometry quiz question

Question

B is the midpoint of AC. AB = 3x + 4 and BC = 2x + 12.  

Find the value of x

for this question I got x=3.2 but idk if im right

Answer 1

Tips:

* Draw a picture.

* Check your answer by substituting it in for x after you've solved-- you want to KNOW if you're right (or not).

* Make sure you've understood each part of the exercise, ie what point B being a midpoint means.

If B is the midpoint-- that is, in the middle-- then the segments AB and BC are the same length, and those expressions equal each other:

3x+4=2x+12

x+4=12

x=8

Check:

3(8)+4=2(8)+12 ?

24+4 = 16+12 ?

28 = 28 !

Note that if you check x = 3.2, you get nonsense: 13.6 = 18.4

Answer 2

B is the midpoint of AC, so AB=BC

3x+4=2x+12

x=8