Melody

CPhill's answer is a good one but it is more common to do it the other way around.

consider this

2(3a) this is 2 lots of 3a and the answer is 2*3a=6a

2(3a+4) is 2 lots of (3a+4) which is 2 lots of 3a plus 2 lots of 4 = 6a+8

(2+3)(3a+4) is 5 lots of (3a+4) but this can also be thought of as 2 lots of (3a+4) plus 3 lots of (3a+4)

so

$$(2a-b)(3a-2b)\\
= 2a(3a-2b) -b(3a-2b)\\
=6a^2-4ab -3ab--2b^2\\
=6a^2-4ab -3ab+2b^2\\
=6a^2-7ab+2b^2\\$$

See, our answers are the same. 

Start with the inner most brackets and work your way out.

$$10+4-(3-(1+2-(4-9)))\\
=14-(3-(3-(-5)))\\
=14-(3-(3--5))\\
=14-(3-(8))\\
=14-(3-8)\\
=14--5\\
=14+5\\
=19$$

CPhill is right but normally percent profit is worked out on cost price.

So if cost price is $20  and sale price is $25 then profit is $5

Percent profit is usually considered to be profit/cost price * 100% 

5/20*100% = 25%

Firstly, do you mean

$$4B^3-1b+2b+2b^3+2b \mbox{ ? }$$    

If so the most common way to write it (for question askers) is 4B^3-1b+2b+2b^3+2b

The hat ^ is used for 'to the power of'.  That is a handy thing for you to know.

Now back to the question, as I have interpreted it.

It is very unusual to use a little b and a Capital B in the same question but I am going to assume that they are different pronumerals that you cannot add or subtract together.

You can only add and subtract like terms - these must have the same letters (pronumerals) and the letters must be raised to the same power.

The only terms you can add are -1b+2b+2b which equals 3b

so the answer is $$4B^3+2b^3+3b$$

Hi Usher,

Welcome to Web2.0calc forum.  We hope you like it here.

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Thanks reinout.  You should look at that site Usher.

Has your question been answered?  It might help if you ask a more specific question.

Thank you Mathcalc and BlindxD,

We do try our best to help and its really nice when people show appreciation. 

Good one anonymous.  Why don't you join up and have a unique name.  

Hi everyone,

There were lots of great answers delivered today by Alan, CPhill, Rom, Bioschip, Admin and Bertie.  There were also a couple of good answers from anonymouse people.  Thank you everyone, your efforts are much appreciated.

It is nice to see that someone other than me and admin is using the thumbs up system.  This is just a way for you to say that you appreciated an answer.  I would really like people to make more use of this system that Andre has set in place for us.

Andre now has a basic messaging system working for us.  This is great, thank you.  

Andre has also changed the second tab to 'Answers'.  I haven't used it yet so I can't comment on its merits.  Sorry.

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I think I liked this question and answer (by CPhill alternatively known as Chris) best today.

I also want to look at this answer by Alan,  The first line is obvious but after that - I have to think about it.

And lastly this question by CountryGirl333 gained a lot of attention.  CountryGirl interacted with answerers and this is always appreciated.  Thank you CountryGirl333    It is good when we all get to interact with each other.

I am not at home at present and my access to the internet is poor.  If I am quieter than usual that is probably why.  Rural Australia has poor internet access.  Although I am on the coast, not inland, so there is at least some coverage.

That's it for this Easter Sunday day/night.

Melody.

The messaging system is now working in a very basic way but you can still email me at

melodymathforum@gmail.com

I have a different take on this.

I think everyone has assumed that 83,63 and 100 are all percentages, or at least out of the same total.

What if they were not.   Then if they were all equal in weighting they would need to be converted to the same denominator.  Probably converted to a percentage.  Then they could be averaged to get the final score.

Or, did you mean

$$(x+7)^2=19\\\\
x+7 = \sqrt{19} \mbox{ or }x+7=-\sqrt{19}\\\\
x = \sqrt{19}-7 \mbox{ or }x=-\sqrt{19}-7\\\\$$

If this is what you meant then you should have used the superscipt button from the fromat heading to write the 2  OR you could write

(x+7)^2=19

The ^ (hat) means 'power of'.