Melody

Good question!

Two minus make a plus ONLY

1) if they are so close together that you can put a circle around them and there is nothing else in  the circle.

Think of it like this if you want

Negative numbers are cold numbers.  Like -30degrees would be very cold wouldn't it?

and Positive numbers are hot numbers.  An oven might be 180degrees. There is an invisible + in front of the 180.

So 15--2 means you are taking away cold - so it must get hotter

15--2=15+2=17

2) If you are multiplying or dividing

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NOW if you are adding or subtracting positive and negative numbers then you need to think about a number line.

10+3 means you start at 10 and go 3 places in the positive direction = 13

10-3 means you start at 10 and go 3 places in the negative direction = 7

Just continue this method with trickier negative numbers

-3-8 means you start at -3 and go 8 places in the negative direction = -11

OR to put it another way.  It is -3 degrees and it gets 8 degrees COLDER = -11 degrees

So lets look at your question

-7+-8 = If you add cold it gets colder so the question becomes

-7-8     Now if it is -7 degrees that pretty cold and you take away 8 degrees, it is going to get even colder! So the answer must be more negative.  

Start at -7 on the number line and go 8 places in the negative direction.  The answer is -15

I don't know why I am writing all this I am sure that I have done it before as a post to keep.  Not to worry.

Here is a number line that might help you. You'll have to add the negative numbers in yourself.

Here is a site that might also help.   

http://www.mathsisfun.com/positive-negative-integers.html

It is just 6 divided by 0.9

you can do it youself on the home page calcualtor.  

$$x-y=\pm8$$

So as CPhill said, there are infinite solutions.

ALL the points on these two lines will satisfy the equation.

You use trigonometry.

If there is a right angle it is very simple trig. (Use 'inverse trig' which is 'arc trig' here)

If there is not right angle then you have to use the cosine rule.

What mini user guide are you talking about anonymous?

Hi reddragon08,

I see that you are new,

Welcome to web2.calc forum.  We hope you find this site useful and fun.

If you want to ask a question - well you know how to do that - you just did.

Just muck around with the features on the page.   It's pretty easy.

Melody.

I am not sure what you really meant but;

$$\begin{array}{rll}
\sqrt3(x+2)-6&=&-2\\\\
\sqrt3(x+2)&=&4\\\\
x+2&=&\dfrac{4}{\sqrt3}\\\\
x+2&=&\dfrac{4\sqrt3}{3}\\\\
x&=&\dfrac{4\sqrt3}{3}-2\\\\
x&=&\dfrac{4\sqrt3-6}{3}\\\\
\end{array}$$

Look in the Sticky notes at bottom right of page

You will find your answer there.

Well, Someone Who Knows Everything, I stand corrected.

How many forums do you troll anyway?  Where do you find the time?

Look in the Sticky Topics. Bottom right of page.  There's one on typing in fractions.