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rachelmaddie

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I need my work checked please.
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The raffle prize (in dollars) is given by the following expression: 14x^2/15
Since it is to be divided among 7x people, the expression can be written like this to describe the amount of money that each person will receive.
14x^2/15(7x)
Then simplify the expression:
= 14x^2/15(1/7x)
= 14x^2/15*7x
= 14x^2/105x
= 2x/15 (The numerator and denominator is divided by 7x)
Therefore, each person would receive 2x/15 dollars.
 
rachelmaddie said:
I need my work checked please.
View attachment 20545
The raffle prize (in dollars) is given by the following expression: 14x^2/15
Since it is to be divided among 7x people, the expression can be written like this to describe the amount of money that each person will receive.
14x^2/15(7x)
Then simplify the expression:
= 14x^2/15(1/7x)
= 14x^2/15*7x
= 14x^2/105x
= 2x/15 (The numerator and denominator is divided by 7x)
Therefore, each person would receive 2x/15 dollars.
Click to expand...
Your numerical answer is correct - but the details have mistakes.
 
You have the correct answer, but your carelessness with parentheses might cost you some part credit.
 
rachelmaddie said:
What mistakes?
Click to expand...
You write:

14x^2/15(7x)

This - according to PEMDAS - translates to:

14*x^2 / 15 * (7 * x) = 14*x^2 * (7 * x) / 15

You should have written:

14x^2/(15*7x) ......................... or

You should have written:

(14x^2/15) / (7x)
 
For starters, look at your first expression: 14x^2/15(7x). Is that 7x in the denominator or numerator? Perhaps if you were writing it by hand it would be obvious, but not as written here. You might write it as (14x^2/15)(1/(7x)). Displaying expressions like this is why you might want to spend a few minutes looking at the TeX support on this forum. Then you could write it like you might on paper:
[MATH]\frac{14x^2}{15\cdot 7x}[/MATH]
 
LCKurtz said:
For starters, look at your first expression: 14x^2/15(7x). Is that 7x in the denominator or numerator? Perhaps if you were writing it by hand it would be obvious, but not as written here. You might write it as (14x^2/15)(1/(7x)). Displaying expressions like this is why you might want to spend a few minutes looking at the TeX support on this forum. Then you could write it like you might on paper:
[MATH]\frac{14x^2}{15\cdot 7x}[/MATH]
Click to expand...
Like this?
(14x^2)/(15(7x))
Then simplify the expression:
= (14x^2)/(15(1/7x))
= (14x^2)/(15*7x)
= 14x^2/105x
= 2x/15 (The numerator and denominator is divided by 7x)
 
rachelmaddie said:
Like this?
(14x^2)/(15(7x))
Then simplify the expression:
= (14x^2)/(15(1/7x))
= (14x^2)/(15*7x)
= 14x^2/105x
= 2x/15 (The numerator and denominator is divided by 7x)
Click to expand...
Why would you think that the two red expressions are equal?
 
I'm saying the two expressions in red are not equal. So something is wrong with your interpretation of what the parentheses do. Again, as I suggested in post #7, TeX would likely help you with this kind of thing.
 
LCKurtz said:
I'm saying the two expressions in red are not equal. So something is wrong with your interpretation of what the parentheses do. Again, as I suggested in post #7, TeX would likely help you with this kind of thing.
Click to expand...
I dont know what TeX is. Can you please show me what I’ve done incorrectly with the parentheses?
 
It is hard to say what you are doing wrong when I don't know what you are thinking you have written. In the two example expressions I highlighted in red you have parentheses around both putting each expression 15(7x) and 15(1/7x) in the denominator. Those expressions obviously aren't equal. I don't know what else to say because I don't know why you would think they are equal. Why would you replace 7x with 1/7x?
 
LCKurtz said:
It is hard to say what you are doing wrong when I don't know what you are thinking you have written. In the two example expressions I highlighted in red you have parentheses around both putting each expression 15(7x) and 15(1/7x) in the denominator. Those expressions obviously aren't equal. I don't know what else to say because I don't know why you would think they are equal. Why would you replace 7x with 1/7x?
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The (1/7)x) is an error.
 
Well, that's the kind of thing I was referring to when I told you you would lose credit for carelessness with parentheses. Delete that line and the rest in post #8 looks OK.
 
LCKurtz said:
Well, that's the kind of thing I was referring to when I told you you would lose credit for carelessness with parentheses. Delete that line and the rest in post #8 looks OK.
Click to expand...
(14x^2)/(15(7x))
Then simplify the expression:
= (14x^2)/(15(7x))
= 14x^2/105x
= 2x/15 (The numerator and denominator is divided by 7x)

How is this?
 
rachelmaddie said:
(14x^2)/(15(7x))
Then simplify the expression:
= (14x^2)/(15(7x))
= 14x^2/105x\(\displaystyle \ \ \ \ \ \ \ \)Make it 14x^2/(105x).
= 2x/15 (The numerator and denominator is divided by 7x)

How is this?
Click to expand...


As I showed, you need grouping symbols around that denominator.
 
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