You will have to get the -3x by itself so you will add 6 to both sides so -3x-6+6-5+6 and you will get -3x=11do you need anymore help?
12 m is the area! hope i could help
Can you give more information on your question?
Answer:
7.5
Step-by-step explanation:

V = s^2(h/3)
is the formula....................<span />