explain this to me
The cube root of a number is between 7 and 8. Which of the following could be the value of that number?
A- 344
B- 320
C- 550
D- 600
algebra help?
2016-06-10 2:05 am
回答 (4)
2016-06-10 2:08 am
✔ 最佳答案
Okay, first let's figure out what 7^3 is.7x7x7 = 343
Let's figure out what 8^3 is
8x8x8 = 512
Now we know that our number has to be between 7 and 8 so that tells us that our number cubed has to be between our values for 7^3 and 8^3.
Now we can just cancel out anything that doesn't fit.
320 is too small and 550 and 600 are too large.
The only thing that falls into our range is 344.
A
2016-06-10 2:18 am
7^3 = 343
8^3 = 512
Only 344 is between 343 and 512 so it is the answer.
8^3 = 512
Only 344 is between 343 and 512 so it is the answer.
2016-06-10 2:09 am
I would look at the upper and the lower limit. The statement says between 7 and 8.
If I do 7 x 7 x 7 = 343
If I do 8 x 8 x 8 = 512
Now the only number between 343 and 512 in the list you provided is 344.
If I do 7 x 7 x 7 = 343
If I do 8 x 8 x 8 = 512
Now the only number between 343 and 512 in the list you provided is 344.
2016-06-10 2:06 am
7 < ∛x < 8
7³ < x < 8³
343 < x < 512
7³ < x < 8³
343 < x < 512
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