Answer:
x = 5
Step-by-step explanation:
B, bisects AB. So, AB = BC
AC = AB +BC
= AB + AB
AC = 2AB
[tex]\dfrac{1}{2}AC = AB\\\\AB = \dfrac{1}{2}AC\\\\2x + 10 =\dfrac{1}{2}*40\\\\2x + 10 = 20[/tex]
Subtract 10 from both sides,
2x = 20 - 10
2x = 10
Divide both sides by 2
x = 10/2
x = 5
