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How do you do these math questions?

These are polynomials:

A rectangle's length is 7 cm greater than it's width, w.

A) Draw a rectangle and label its dimensions. I drew the rectangle and labeled the width as 7w on each side and 14w on the legth of each side. Is this correct?

B) Write an expression to find its perimeter.  I wrote : 7w=14w=7w=14w  and got 42w. Is this correct?

C) Collect like terms. I did that. 7w & 7w  14w & 14w Is this correct?

 

I have troubles with this problem as well.

The cost of publishing the school yearbook was $440. The yearbook committee priced the yearbook at $8.

A) Write an expression that represents the profit, p, for the number of yearbooks sold, n.

Not sure?

B) How many yearbooks need to be sold for the yearbook committee to break even?

Not sure what that last part meant...

 

Help please and thank you all.

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1 Answer

The rectangle problem first:

The problem states that the length is 7cm greater than the width.  If we call L the length and W the width then the rectangle should have the shorter widths labeled "W" and the longer sides labeled "L = 7 + W".

The parameter of a rectangle is (2*L)+(2*W).  In this case L = 7+W.  So we would rewrite the equation as follows: P = 2*(7+W) + 2*W

This would expand to be P = 14 + 2*W + 2*W

We can now combine like terms and we will get: P = 14 + 4W

 

For the year book problem:

If you are looking for profit you have to make more than you spend.  You spent $440 and each book retails for $8.

Therefore, if 8*n>440 then you have made profit, where n is the number of yearbooks. if in fact 8*n>440, then your profit will be (8*n)-440 iff(if and only if) 8*n>440

To find out how many need to be solt to break even the expression changes to: 8*n = 440

This is because you are just wanting to know what it takes to make what you spent. You would then divide 440 by 8 to get n = 440/8. Which is your answer to breaking even.