AnExtremelyLongName

Hello BIGChungus!  I like your name!
 

Plan:

For arithmetic problems, I like using variables.

First term = x

Common difference = y

We can define an arithmetic sequence this way:

x + (x + y) + (x + 2y) + (x + 3y)....

Set up and solve:

(1) $\frac{a_4}{a_2}=\frac{x+3y}{x+y}=3$

(2) $\frac{a_5}{a_3}=\frac{x+4y}{x+2y}=?$

Let us get rid of the fraction in (1) by multiplying both sides by (x+y)

x + 3y = 3x + 3y

-2x = 0

x = 0

Wow! The first term is 0.

Let us plug that into (2).

$\frac{0+4y}{0+2y}$

Simplify

$\frac{4y}{2y}=2$

Ta-da! Mathz! 

I may have noticed his error. (4, -8) is supposed to be (3, -8). You may use his method and solve it correctly now.

I only give a thumbs down if someone (usually a guest) is being insulting. I've done that a couple of times looking through old posts.

You are welcome! I am happy that you appreciate my answer! 

Yes I know. What are you implying? There are multiple ways to solve this.

 - The easiest (in my opinion) is my first post.

 - Another method is to apply the law of cosines to solve for the last missing side, then use Heron's Formula to calculate the area

There may be more!

Hello sandwich!

Let $x$ be the number of weeks.

Barb is SPENDING. So he/she is represented as $800-30x$

Clair is SAVING. So he/she is represented as $300+20x$

Set the two expression equal to each other in order to fufill the question.

$800-30x=300+20x$

Now solve for $x$

Example:

Write 125% as a fraction and as a decimal

$\frac{125}{100}=\frac{5}{4}=1.25$

Now it's your turn!

Do you know how to convert from a base to base 10?

If so, I recommend you convert the numbers into base 10. Compute it. Then convert back into base 12.

If you do not know, I recommend to take a look again at your textbook or whatever online lesson you are taking. I am sure they have taught you the basics of base conversions and calculations.

There seems to be two variables in your expression. If that is all to the problem, the only thing I can think for you to do is express your answer in those two variables in base 12.