The only number not divisible by anything except itself and 1, was C. 7
Answer:
8 days
Step-by-step explanation:
On day 8, Isabella will save 256 nickels, bringing her total to 510.
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The number of nickels saved on day n is 2^n. The total is 2^(n+1)-2.
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The above can be written down from your knowledge of binary sequences. If you want a more formal development, read on.
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The number of nickels saved on day n is a geometric sequence with first term 2 and common ratio 2. The n-th term of the sequence is ...
an = a1·r^(n-1) = 2·2^(n-1) = 2^n
The sum of n terms of the sequence is ...
S = a1(r^n -1)/(r -1) = 2(2^n -1)/(2-1)
S = 2^(n+1) -2
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We want S > 500, so ...
500 < 2^(n+1) -2
502 < 2^(n+1)
251 < 2^n
log(251) < n·log(2)
n > log(251)/log(2)
n > 7.97 . . . . . . . . 8 days or more to save more than 500 nickels
The solutions to the system of equations are (-2,-6) and (4,6)
<h3>How to determine the system of equations?</h3>
We have:
-2x + y = -2
Next, we plot the graph of both functions.
From the attached graph, the equations intersect at (-2,-6) and (4,6)
Hence, the solutions to the system of equations are (-2,-6) and (4,6)
Read more about system of equations at:
brainly.com/question/21405634
#SPJ1
Answer:(x-3)(x-4)
Step-by-step explanation:Basically, the intercepts of the graph, 3 and 4, are when the graph is equal to zero, which is why is (x-3)(x-4) and not (x+3)(x+4).
Just squish the two equations into one equation and idk im just typing this because i apparently need a twenty character long answer
