Numbers Finder by Sum and Product

Enter the sum and product of two numbers to find them instantly!

Calculate Two Numbers from Their Sum and Product

Result

How to Calculate Two Numbers from Their Sum and Product

Given:

  • \( S \): the sum of two numbers
  • \( P \): the product of two numbers

Steps:

  1. Establish relationships: \( x + y = S, \quad x \cdot y = P \)
  2. Express \( x \) in terms of \( y \): \( x = S - y \)
  3. Substitute into the product equation: \( y^2 - Sy + P = 0 \)
  4. Solve the quadratic equation using the quadratic formula: \( y = \frac{S \pm \sqrt{S^2 - 4P}}{2} \)
  5. Find \( x \): \( x = S - y \)

Examples

Example 1: The sum of two numbers is 100, and their product is 99. Find the numbers.

Solution:

1. Quadratic equation:

\( y^2 - 100y + 99 = 0 \)

2. Discriminant:

\( \sqrt{100^2 - 4 \cdot 99} = \sqrt{9604} = 98 \)

3. Roots:

\( y_1 = \frac{100 + 98}{2} = 99 \),\( y_2 = \frac{100 - 98}{2} = 1 \)

\( x_1 = S - y_1 = 100 - 99 = 1 \)

\( x_2 = S - y_2 = 100 - 1 = 99 \)

Result: The two numbers are 99 and 1.

Example 2: The sum of two numbers is 45, and the product is 500. Find the numbers.

Solution:

1. Quadratic equation:

\( y^2 - 45y + 500 = 0 \)

2. Discriminant:

\( \sqrt{45^2 - 4 \cdot 500} = \sqrt{25} = 5 \)

3. Roots:

\( y_1 = \frac{45 + 5}{2} = 25 \),\( y_2 = \frac{45 - 5}{2} = 20 \)

\( x_1 = S - y_1 = 45 - 25 = 20 \)

\( x_2 = S - y_2 = 45 - 20 = 25 \)

Result: The two numbers are 25 and 20.

Example 3: The sum of two numbers is 25, and the product is 144. Find the numbers.

Solution:

1. Quadratic equation:

\( y^2 - 25y + 144 = 0 \)

2. Discriminant:

\( \sqrt{25^2 - 4 \cdot 144} = \sqrt{49} = 7 \)

3. Roots:

\( y_1 = \frac{25 + 7}{2} = 16 \),\( y_2 = \frac{25 - 7}{2} = 9 \)

\( x_1 = S - y_1 = 25 - 16 = 9 \)

\( x_2 = S - y_2 = 25 - 9 = 16 \)

Result: The two numbers are 16 and 9.

Example 4: The sum of two numbers is 62, and their product is 960. Find the numbers.

Solution:

1. Quadratic equation:

\( y^2 - 62y + 960 = 0 \)

2. Discriminant:

\( \sqrt{62^2 - 4 \cdot 960} = \sqrt{484} = 22 \)

3. Roots:

\( y_1 = \frac{62 + 22}{2} = 42 \),\( y_2 = \frac{62 - 22}{2} = 20 \)

\( x_1 = S - y_1 = 62 - 42 = 20 \)

\( x_2 = S - y_2 = 62 - 20 = 42 \)

Result: The two numbers are 42 and 20.