First,B bisects AC, this means that B dovids AC into two equal halves. therefore AB=AC
second and third steps are just isolating the terms containg y on one side of the equation and the other terms on the other side.
finally you have 3y=15, to get the value of y,you divide both sides of the equation by 3.
Answer:

Step-by-step explanation:
Combining like-terms gives us 
Hope this helped!
Answer:
4.5
Step-by-step explanation:
1 yard = about 1 meter
Whats the rest of the question?