Answer:
destroy the teacher muhahahahahahahahaha
Step-by-step explanation:
![\sqrt[3]{64}=4](https://tex.z-dn.net/?f=%5Csqrt%5B3%5D%7B64%7D%3D4)
so it's obvious, I guess :)
Now, let's prove ![\sqrt[3]{12}](https://tex.z-dn.net/?f=%5Csqrt%5B3%5D%7B12%7D)
is not rational number.
Proof by contradiction.
Let assume is a rational number. Therefore it can be expressed as a fraction 
where 
and 
.
![\sqrt[3]{12}=\dfrac{a}{b}\\\\12=\dfrac{a^3}{b^3}\\\\a^3=12b^3](https://tex.z-dn.net/?f=%5Csqrt%5B3%5D%7B12%7D%3D%5Cdfrac%7Ba%7D%7Bb%7D%5C%5C%5C%5C12%3D%5Cdfrac%7Ba%5E3%7D%7Bb%5E3%7D%5C%5C%5C%5Ca%5E3%3D12b%5E3)
is an even number, so 
must also be an even number, and therefore also 
must be an even number. So, we can say that 
, where 
.
Since 
is an even number, then also 
must be an even number. 3 is odd, so for to be an even number, 
must be an even number, and therefore 
is an even number.
But if both a and b are even numbers, then it contradicts our earlier assumption that . Therefore is not a rational number.
Thanks, you two, bless you.
Answer:
a)
10 markers : 7 USD
24 markers : 14 USD
42 markers : 21 USD
b)
64 markers : 28 USD
Step-by-step explanation:
10 markers : 7 USD
24 markers : 14 USD
For 10 markers, the price is 7 USD;
For 14 additional markers, the price increased by 7 USD;
Following the pattern, an additional 18 markers would see the price further increase by 7 USD;
So:
24 + 18 = 42
42 markers : 21 USD
Then, an additional 22 markers would cost 7 USD more than this;
42 + 22 = 64
64 markers : 28 USD
