The average length of the eight words betty was asked to spell was 9 letters. the first seven words had the following lengths: 8 letters, 9 letters, 6 letters, 10 letters, 7 letters, 9 letters, and 11 letters. what was the length of the eighth word?

Step-by-step explanation:

If angles C and B have equal degrees then the side AC is also equal to  side AB in length and you can make their equations equal as well and solve for X.

2x+16=7x+6

get X's all on same side and the constants all on the other side,  

-2x +2x+16=7x+6+-2x

The X's on the left cancel out.

16=5x+6

-6+16=5x+6+-6

add -6 to each side.  On the right the 6 is now cancelled out.

10=5X

divide each side by 5 to cancel out the 5

10/5= 5X/5

2=X .  ANSWER