the difference between integers is 5. their product is 500. find the numbers.
What are two numbers whose difference is 5 and whose product is 500?
Answer:
To solve this problem, we need to set up an equation based on the conditions given: the difference between the two integers is 5, and their product is 500.
Step 1: Setting Up the Equations
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Define the Variables:
- Let the two integers be x and y.
- Given that x - y = 5.
- Given that x \cdot y = 500.
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Rewrite x in Terms of y:
- From the equation x - y = 5, we can express x as:
$$x = y + 5$$
- From the equation x - y = 5, we can express x as:
Step 2: Substituting and Solving
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Substitute x in the Product Equation:
- Substitute x = y + 5 into the equation x \cdot y = 500:
$$(y + 5) \cdot y = 500$$
- Substitute x = y + 5 into the equation x \cdot y = 500:
-
Expand and Simplify:
- Expand the equation:
$$y^2 + 5y = 500$$
- Expand the equation:
-
Rearrange into Standard Quadratic Form:
- Rearrange the terms to get a standard quadratic equation:
$$y^2 + 5y - 500 = 0$$
- Rearrange the terms to get a standard quadratic equation:
Step 3: Solving the Quadratic Equation
-
Use the Quadratic Formula:
- The quadratic formula for ax^2 + bx + c = 0 is:y = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}
- Here, a = 1, b = 5, c = -500.
- The quadratic formula for ax^2 + bx + c = 0 is:
-
Calculate the Discriminant:
- Calculate the discriminant (b^2 - 4ac):
$$5^2 - 4 \cdot 1 \cdot (-500) = 25 + 2000 = 2025$$
- Calculate the discriminant (b^2 - 4ac):
-
Find y Using the Quadratic Formula:
- Substitute the values into the quadratic formula:y = \frac{-5 \pm \sqrt{2025}}{2}
- Evaluate the square root and solve:
- \sqrt{2025} = 45
- Substitute the values into the quadratic formula:
-
Calculate the Two Possible Values for y:
- y = \frac{-5 + 45}{2} = 20
- y = \frac{-5 - 45}{2} = -25
Step 4: Determine Corresponding Values for x
-
For y = 20:
- Substitute back to find x:
$$x = y + 5 = 20 + 5 = 25$$
- Substitute back to find x:
-
For y = -25:
- Substitute back to find x:
$$x = y + 5 = -25 + 5 = -20$$
- Substitute back to find x:
Final Answer:
The two pairs of integers that satisfy the given conditions are:
- (20, 25)
- (-25, -20)
Both pairs meet the criteria of having a difference of 5 and a product of 500.