The dimensions for the pool would be (y+2)(4y-5)
Answer:
Step-by-step explanation:
He collected a total of 225 stamps. If 88% of the stamps he collected were foreign, how many other stamps did he collect?
We can write a system of equations:
1x + 10y = 182
x + y = 56
Where 'x' is the number of $1 bills, and 'y' is the number of $10 bills.
To find this we can solve using substitution.
Re-arrange the 2nd equation:
x + y = 56
Subtract 'y' to both sides:
x = -y + 56
Now we can plug in '-y + 56' for 'x' in the first equation.
1x + 10y = 182
1(-y + 56) + 10y = 182
-y + 56 + 10y = 182
Subtract 56 to both sides:
-y + 10y = 126
Combine like terms:
9y = 126
Divide 9 to both sides:
y = 14
Now we can plug this into any of the two equations to find the 'x' value.
x + y = 56
x + 14 = 56
Subtract 14 to both sides:
x = 42
So our final answer is (42, 14).
This means that the motel clerk had 42 $1 bills, and 14 $10 bills.
<h3>
Answer: Choice B</h3><h3>
y = x^2 + 7x + 1</h3>
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Proof:
A quick way to confirm that choice B is the only answer is to eliminate the other non-answers.
If you plugged x = 1 into the equation for choice A, you would get
y = -x^2 + 7x + 1
y = -1^2 + 7(1) + 1
y = -1 + 7 + 1
y = 7
We get a result of 7, but we want 9 to be the actual output. So choice A is out.
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Repeat for choice C. Plug in x = 1
y = x^2 - 7x + 1
y = 1^2 - 7(1) + 1
y = 1 - 7 + 1
y = -5
We can eliminate choice C (since again we want a result of y = 9)
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Finally let's check choice D
y = x^2 - 7x - 1
y = 1^2 - 7(1) - 1
y = 1 - 7 - 1
y= -7
so choice D is off the list as well
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The only thing left is choice B, so it must be the answer. It turns out that plugging x = 1 into this equation leads to y = 9 as shown below
y = x^2 + 7x + 1
y = 1^2 + 7(1) + 1
y = 1 + 7 + 1
y = 9
And the same applies to any other x value in the table (eg: plugging in x = 3 leads to y = 31, etc etc).
