Math Problem Statement

Solve the equation √(x^2 + 2x + 8) = 12 - 2x.

Solution

The image shows the following mathematical expression:

x2+2x+8=122x\sqrt{x^2 + 2x + 8} = 12 - 2x

We need to solve for xx.

Steps to solve:

  1. Square both sides to eliminate the square root: (x2+2x+8)2=(122x)2(\sqrt{x^2 + 2x + 8})^2 = (12 - 2x)^2 This simplifies to: x2+2x+8=(122x)2x^2 + 2x + 8 = (12 - 2x)^2

  2. Expand the right-hand side: (122x)2=14448x+4x2(12 - 2x)^2 = 144 - 48x + 4x^2 So, the equation becomes: x2+2x+8=14448x+4x2x^2 + 2x + 8 = 144 - 48x + 4x^2

  3. Move all terms to one side: Bring all terms to the left-hand side: x2+2x+8144+48x4x2=0x^2 + 2x + 8 - 144 + 48x - 4x^2 = 0 Simplify the terms: 3x2+50x136=0-3x^2 + 50x - 136 = 0

  4. Solve the quadratic equation using the quadratic formula: The quadratic equation is in the form ax2+bx+c=0ax^2 + bx + c = 0, where: a=3,b=50,c=136a = -3, \, b = 50, \, c = -136 The quadratic formula is: x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} Substituting the values of aa, bb, and cc: x=50±5024(3)(136)2(3)x = \frac{-50 \pm \sqrt{50^2 - 4(-3)(-136)}}{2(-3)} Simplifying inside the square root: x=50±250016326x = \frac{-50 \pm \sqrt{2500 - 1632}}{-6} x=50±8686x = \frac{-50 \pm \sqrt{868}}{-6} x=50±29.456x = \frac{-50 \pm 29.45}{-6}

  5. Find the two possible solutions: x1=50+29.45620.5563.425x_1 = \frac{-50 + 29.45}{-6} \approx \frac{-20.55}{-6} \approx 3.425 x2=5029.45679.45613.24x_2 = \frac{-50 - 29.45}{-6} \approx \frac{-79.45}{-6} \approx 13.24

Thus, the two solutions for xx are approximately: x3.425orx13.24x \approx 3.425 \quad \text{or} \quad x \approx 13.24

Would you like more details on any of the steps, or have further questions?

Here are 5 related questions you might consider:

  1. How do we check if both solutions satisfy the original equation?
  2. What happens if we change the constants in the equation?
  3. Can we solve this quadratic equation graphically? What would the graph look like?
  4. What is the significance of the discriminant in the quadratic formula?
  5. Can this method be applied to similar equations involving square roots?

Tip: Always check both solutions by substituting them back into the original equation to ensure they are valid!

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Math Problem Analysis

Mathematical Concepts

Algebra
Square Roots
Quadratic Equations

Formulas

Quadratic equation formula: ax^2 + bx + c = 0
Square root equation: √(expression) = expression

Theorems

Quadratic formula
Properties of square roots

Suitable Grade Level

Grades 10-12