107k views
3 votes
The cube of the difference of a number and eight

User Geisshirt
by
7.9k points

1 Answer

2 votes

After solving the equations x^3 + y^3 = 243, the difference between the two numbers is found to be 3. Here option A is correct.

Let's denote the first number as x and the second number as y. The given information can be expressed as equations:

The cube of a number is 8 times the cube of another number:

x^3 = 8y^3

The sum of the cubes of the numbers is 243:

x^3 + y^3 = 243

Now, we need to find the difference of the numbers, which is |x - y|. We can try to solve these equations simultaneously to find the values of x and y.

Substitute the first equation into the second one:

8y^3 + y^3 = 243

Combine like terms:

9y^3 = 243

Divide by 9:

y^3 = 27

Take the cube root of both sides:

y = 3

Now, substitute y = 3 into the first equation to find x:

x^3 = 8(3)^3

x^3 = 8 * 27

x^3 = 216

Take the cube root of both sides:

x = 6

Now, find the difference |x - y|:

|6 - 3| = 3

Therefore, the correct answer is (a) 3.

Complete question:

The cube of a number is 8 times the cube of another number. If the sum of the cubes of numbers is 243, the difference of the numbers is:

(a) 3

(b) 4

(c) 6

(d) None of these

User MPawlak
by
8.2k points