The Sum of the Reversed Number and Twice the Original Number

Oct 13, 2025 by miodeya.com 148 views

Express the Number Algebraically: A Positive Number with a Product of Digits 8

In this article, we will explore a mathematical problem that involves a positive number with a product of its digits equal to 8. The problem requires us to find the algebraic expression of this number and then use it to solve a system of equations. We will use variables to represent the digits of the number and then manipulate the equations to find the solution.

A positive number is such that the product of its digits is 8. The sum of the reversed number and twice the original number is 18 more than its reverse. We need to find the algebraic expression of this number.

Let's Represent the Number Algebraically

Let's assume that the number is represented by the variable $x$ in the tens place and $y$ in the units place. The number can be expressed as $10x + y$ . The product of its digits is 8, so we can write the equation:

xy = 8

We can also represent the reversed number as $10y + x$ .

The Sum of the Reversed Number and Twice the Original Number

The sum of the reversed number and twice the original number is 18 more than its reverse. We can write the equation:

(10y + x) + 2(10x + y) = (10x + y) + 18

Simplifying the equation, we get:

10y + x + 20x + 2y = 10x + y + 18

Combine like terms:

12y + 21x = 10x + y + 18

Subtract $10x$ and $y$ from both sides:

11y + 11x = 18

Divide both sides by 11:

y + x = \frac{18}{11}

The Product of the Digits is 8

We know that the product of the digits is 8, so we can write the equation:

xy = 8

We can also represent the product of the digits as $(x + y)^2 - (x - y)^2$ . Expanding the equation, we get:

(x + y)^2 - (x - y)^2 = 8

Simplifying the equation, we get:

x^2 + 2xy + y^2 - (x^2 - 2xy + y^2) = 8

Combine like terms:

4xy = 8

Divide both sides by 4:

xy = 2

Solving the System of Equations

We have two equations:

y + x = \frac{18}{11}

xy = 2

We can solve the system of equations by substitution or elimination. Let's use substitution.

Rearrange the first equation to isolate $y$ :

y = \frac{18}{11} - x

Substitute this expression for $y$ into the second equation:

x(\frac{18}{11} - x) = 2

Expand the equation:

\frac{18x}{11} - x^2 = 2

Multiply both sides by 11:

18x - 11x^2 = 22

Rearrange the equation to get a quadratic equation:

-11x^2 + 18x - 22 = 0

Divide both sides by -1:

11x^2 - 18x + 22 = 0

Solving the Quadratic Equation

We can solve the quadratic equation using the quadratic formula:

x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}

In this case, $a = 11$ , $b = -18$ , and $c = 22$ . Plugging these values into the formula, we get:

x = \frac{-(-18) \pm \sqrt{(-18)^2 - 4(11)(22)}}{2(11)}

Simplify the equation:

x = \frac{18 \pm \sqrt{324 - 968}}{22}

x = \frac{18 \pm \sqrt{-644}}{22}

Since the square root of a negative number is not a real number, we have a complex solution.

In this article, we explored a mathematical problem that involved a positive number with a product of its digits equal to 8. We represented the number algebraically using variables and then used the equations to solve a system of equations. We found that the solution to the system of equations is a complex number, which means that the problem does not have a real solution.

[1] "Algebraic Expressions" by Math Open Reference
[2] "Quadratic Formula" by Math Is Fun

This problem is a great example of how algebraic expressions can be used to solve real-world problems. The use of variables and equations allows us to represent complex relationships between variables and solve for the unknowns.

However, in this case, the problem does not have a real solution, which means that the algebraic expression does not represent a real number. This highlights the importance of carefully checking the solutions to ensure that they are real and meaningful.

[1] "A Positive Number with a Product of Digits 4" by Math Problems
[2] "A Number with a Sum of Digits 9" by Algebraic Expressions

[1] "Algebraic Expressions" by Khan Academy
[2] "Quadratic Formula" by MIT OpenCourseWare
Q&A: Express the Number Algebraically - A Positive Number with a Product of Digits 8

In our previous article, we explored a mathematical problem that involved a positive number with a product of its digits equal to 8. We represented the number algebraically using variables and then used the equations to solve a system of equations. However, we found that the solution to the system of equations is a complex number, which means that the problem does not have a real solution.

In this article, we will answer some of the most frequently asked questions about the problem and provide additional insights and explanations.

Q: What is the product of the digits of the number?

A: The product of the digits of the number is 8.

Q: How do we represent the number algebraically?

A: We can represent the number algebraically using variables. Let's assume that the number is represented by the variable $x$ in the tens place and $y$ in the units place. The number can be expressed as $10x + y$ .

Q: What is the sum of the reversed number and twice the original number?

A: The sum of the reversed number and twice the original number is 18 more than its reverse.

Q: How do we solve the system of equations?

A: We can solve the system of equations by substitution or elimination. Let's use substitution. Rearrange the first equation to isolate $y$ :

y = \frac{18}{11} - x

Substitute this expression for $y$ into the second equation:

x(\frac{18}{11} - x) = 2

Expand the equation:

\frac{18x}{11} - x^2 = 2

Multiply both sides by 11:

18x - 11x^2 = 22

Rearrange the equation to get a quadratic equation:

-11x^2 + 18x - 22 = 0

Q: How do we solve the quadratic equation?

A: We can solve the quadratic equation using the quadratic formula:

x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}

In this case, $a = 11$ , $b = -18$ , and $c = 22$ . Plugging these values into the formula, we get:

x = \frac{-(-18) \pm \sqrt{(-18)^2 - 4(11)(22)}}{2(11)}

Simplify the equation:

x = \frac{18 \pm \sqrt{324 - 968}}{22}

x = \frac{18 \pm \sqrt{-644}}{22}

Since the square root of a negative number is not a real number, we have a complex solution.

Q: What does the complex solution mean?

A: The complex solution means that the problem does not have a real solution. This is because the quadratic equation has no real roots, which means that the system of equations has no real solution.

Q: What are some related problems?

A: Some related problems include:

A positive number with a product of digits 4
A number with a sum of digits 9
A number with a product of digits 16

Q: Where can I find additional resources?

A: You can find additional resources on algebraic expressions and quadratic equations on websites such as Khan Academy and MIT OpenCourseWare.

In this article, we answered some of the most frequently asked questions about the problem and provided additional insights and explanations. We also discussed some related problems and provided additional resources for further learning.

[1] "Algebraic Expressions" by Math Open Reference
[2] "Quadratic Formula" by Math Is Fun

[1] "Algebraic Expressions" by Khan Academy
[2] "Quadratic Formula" by MIT OpenCourseWare