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Absolute value bars guarantee that the answer is positive; if the number inside the absolute value bars is already positive, the answer remains positive. --->  |10|  =  10

28 - (-x) - |10|

--->   28 - (-15) - |10|

--->   28 + 15 - 10

--->   43 - 10

--->   33

Thanks Nauseated, your answer looks good to me  

I thought your snarky comment about being a troll was quite funny :)

Rosala, only one small suggestion, when you do questions like this it makes it easier if you use square brackets as well as round brackets.  It makes it easier to seperate everything properly visually and in your head.  

∑_{i=1 to 5} (-1)^i-1(i/3)ⁱ

-2/5  � 🍰

$$\\
\frac{d}{dx}\;3\times 4(x+2)\\\\
=12\times\frac{d}{dx}(x+2)\\\\
=12\times 1\\\\
=12$$

On this calc it is the same except   inverse tan is atan

Nice answer Geno  

All very interesting. So what is the difficulty in substituting those data values into the equation? There are not any conversions needed, just a direct substitution. 

Almost too easy.  

The shape is like a funnel. The bigger number sits at the bigger side of the funnel.

Euler's constant:

=  0.57721566490...

Euler's number:

=  2.71828182846...

depends on what a and b is.

If you write them with the same number of decimal places, then you are comparing:

0.0008

0.0040

Written this way, it is easy to see that 40 > 8, so 0.004 > 0.0008.

A single waffle iron working flat out can cook 30 waffles in one hour. So to cook 250 waffles in that time you will need how many such irons?

Thers is no such thing as half a waffle iron. So if your calculations come up needing a fraction of an iron, then just round this up to the next highest integer.  

one day has 24 hours

1 hour has 60 minutes

24x60=1440 minutes on 1 day

1440 minutes x 100 million days

= a lot :)

log(x³)+2log(x)-10=0

log(x³)+2log(x)=10

log(x³)+log(x²)=10

log(x^5)=10

10^10=x^5

x=100

on casio fx-82ms

-(tan-1(4/8))=-26.565

tan-1=shiftbutton+tan

4x-24x=-20x

-20x-35=0

-20x=35

35/(-20)=x

x=-1.75

The larger side is on the side of the larger number, i.e.

10>5

-2<2

100>10

To remember, simply imagine " < " as a Pacman who wants to eat the most food. Since 5 food is more than 3 food,  5 > 3.

=10+9

=19

therefore, 10 + 9 = 19

$$\ x^4 - ( x-z)^4 \; \hspace{3ex}\leftarrow \text {Factor} \\
\; \\
\ = \; (x^2)^2 - ((x-z)^2)^2 \\
\ = \; (x^2 - (x-z)^2)(x^2 + (x-z)^2)\\
\ = \; (x - (x-z))(x + (x-z)) (x^2 + x^2)(x^2 + x^2 + z^2 - 2xz)\\
\ = \; (x - x + z)(2x-z)(x^2 + x^2 +z^2 - 2xz)\\
\ = \; z(2x-z)(2x^2 + z^2 - 2xz)$$

_

It is outside my normal nature to post something without a snarky comment.

Rosala, you better check it carefully because I may have a made an intentional mistake. I am a troll, you know!

It is easy enough for any of the top answerers to note my “error” but it doesn’t seem  they are around at the moment.

(l+m)^2-(l-m)^2=(l+m+l-m)(l+m-l+m)=2l*2m=4ml

a^2-b^2=(a+b)(a-b)

Yeah! I know! Thanks!

Thanks Melody!