Melody

Start by adding 7 to both sides.

It does completely different things from Desmos.  But you are right it is not very intuitive.  still just start with little things and it will become easier.

You know, I find set notation confusing enough when it does not involve dresses, dates and proms!

Rosala, ot is ver nice of you to loan Beth your dress.  It is a lovely dress.  Beth will look very sophisticated!

I don't think anyone undersands your question.

No Chris I always use GeoGebra for pictures like this.

It is a free download - well worth it.

It is quite powerful but i don't know how to use it very well.  It is not terrible intuitive but with a bit of mucking around you can draw things like this fairly quickly.

You should download it and have a play.

x/3-8=-6

you can solve it yourself - or at least you can try.

Using Pythagoras' Theorum

$$x^2+x^2=\left(\frac{\sqrt3}{2}\right)^2\\\\
2x^2=\frac{3}{4}\\\\
x^2=\frac{3}{8}\\\\
x=\sqrt{\frac{3}{8}}\\\\
x=\frac{\sqrt3 }{2\sqrt2 }\\\\
x=\frac{\sqrt3 }{2\sqrt2 }\times \frac{\sqrt2}{\sqrt2}\\\\
x=\frac{\sqrt3 \sqrt2 }{2\sqrt2 \sqrt2}\\\\
x=\frac{\sqrt6 }{4}\\\\
Perimeter=4\times \frac{\sqrt6 }{4}=\sqrt6\:\: units\\\\$$

It is not just the first 3 that are in descending order Rosala it is all of them.

Here is a number line - maybe if you think about it you might understand what I am trying to say.

I am just showing how the pattern backs up the idea that a positive multiplied by a negative gives a negative answer.

My book says v = 1/(1+i) is the discount factor and d = i/(1+i) is the discount rate. When do you use which?

No, I don't think that i get it.  normally a with discounts you would talk about i and 1-i (not 1+i) so  I am confused.

Is there more to this that you can show us?

Think about this pattern 

Notice that, on each new line, the number 2 is multiplied by goes down by 1 and the answer goes down by 2.

2*3=6

2*2=4

2*1=2

2*0=0

2*-1=-2

2*-2=-4

2*-3=-6

Can you see the pattern?