Math Problem Statement

what are two numbers that multiply to -6 and add to 4

Solution

To find two numbers that multiply to 6-6 and add to 44, let the numbers be xx and yy. These two numbers must satisfy the equations:

xy=6x \cdot y = -6 x+y=4x + y = 4

Steps to Solve:

  1. From x+y=4x + y = 4, we can express yy in terms of xx: y=4xy = 4 - x

  2. Substitute y=4xy = 4 - x into xy=6x \cdot y = -6: x(4x)=6x \cdot (4 - x) = -6

  3. Expand and simplify: 4xx2=64x - x^2 = -6 x24x6=0x^2 - 4x - 6 = 0

  4. Solve the quadratic equation x24x6=0x^2 - 4x - 6 = 0 using the quadratic formula: x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} Here, a=1a = 1, b=4b = -4, and c=6c = -6: x=(4)±(4)24(1)(6)2(1)x = \frac{-(-4) \pm \sqrt{(-4)^2 - 4(1)(-6)}}{2(1)} x=4±16+242x = \frac{4 \pm \sqrt{16 + 24}}{2} x=4±402x = \frac{4 \pm \sqrt{40}}{2} x=4±2102x = \frac{4 \pm 2\sqrt{10}}{2} x=2±10x = 2 \pm \sqrt{10}

Solutions:

  • The two numbers are: x=2+10,y=210x = 2 + \sqrt{10}, \quad y = 2 - \sqrt{10} OR x=210,y=2+10x = 2 - \sqrt{10}, \quad y = 2 + \sqrt{10}

These numbers multiply to 6-6 and add to 44.


Do you want further details or help visualizing this solution?

Here are 5 related questions to explore:

  1. How can we graphically represent the solution of x24x6=0x^2 - 4x - 6 = 0?
  2. How is the quadratic formula derived, and when is it used?
  3. Can we estimate 10\sqrt{10} to approximate the answers numerically?
  4. How can we check if the two numbers truly satisfy both conditions?
  5. What is the significance of the discriminant in the quadratic formula?

Tip: Always check your solutions by substituting them back into the original equations!

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations
Factoring
Solving Equations

Formulas

Quadratic equation formula: x = (-b ± √(b² - 4ac)) / 2a

Theorems

Quadratic Formula
Properties of Equality

Suitable Grade Level

Grades 8-10