Which expression is a sum of cubes?
2 answers:
<u>ANSWER</u>
<u>EXPLANATION</u>
When we can write an expression in the form
then it is a sum of cubes.
To write a given sum as sum of cubes, then the coefficients of the terms should cube be numbers and the exponents of any power should be a multiple of 3.
This tells us that the first option will be the best choice.
We can rewrite this as:
We apply this property of exponents:
This gives us
Therefore the correct option is A
You might be interested in
First we must understand how to write a logarithmic function:
In the equation above, b is the base, x is the exponent, and a is the answer. These same variables can be rearranged to be expressed as an exponential equation as followed:
Next, we need to understand basic logarithm rules.
1. When a value is raised to a power, we can move the exponent to the front of the logarithm. Example:
log(a^2) = 2log(a)
2. When two variables are multiplied together, we can add the logarithms of the individual variables together. Example:
log(ab) = log(a) + log(b)
3. When a variable is divided by another variable, we can subtract the logarithms of the individual variables. Example:
log(a/b) = log(a) - log(b)
Now we can use these rules to solve the problem.
![log(r)=log( \sqrt[3]{ \frac{A^2B}{C} } )](https://tex.z-dn.net/?f=log%28r%29%3Dlog%28%20%5Csqrt%5B3%5D%7B%20%5Cfrac%7BA%5E2B%7D%7BC%7D%20%7D%20%29)
We can rewrite the cube root as:
Now we can move the one-third to the front:
Now we can split up the logarithm:
Finally, we can move the exponent to the front of the log of A:
Distribute the one-third to get the answer:
The answer is (4).
In the equation above, b is the base, x is the exponent, and a is the answer. These same variables can be rearranged to be expressed as an exponential equation as followed:
Next, we need to understand basic logarithm rules.
1. When a value is raised to a power, we can move the exponent to the front of the logarithm. Example:
log(a^2) = 2log(a)
2. When two variables are multiplied together, we can add the logarithms of the individual variables together. Example:
log(ab) = log(a) + log(b)
3. When a variable is divided by another variable, we can subtract the logarithms of the individual variables. Example:
log(a/b) = log(a) - log(b)
Now we can use these rules to solve the problem.
We can rewrite the cube root as:
Now we can move the one-third to the front:
Now we can split up the logarithm:
Finally, we can move the exponent to the front of the log of A:
Distribute the one-third to get the answer:
The answer is (4).