Math Problem Statement

x(x+9)+24>17

Solution

To solve the inequality x(x+9)+24>17x(x + 9) + 24 > 17, follow these steps:

  1. Simplify the inequality: x(x+9)+24>17x(x + 9) + 24 > 17 First, expand the expression: x2+9x+24>17x^2 + 9x + 24 > 17

  2. Move all terms to one side: Subtract 17 from both sides: x2+9x+2417>0x^2 + 9x + 24 - 17 > 0 Simplify: x2+9x+7>0x^2 + 9x + 7 > 0

  3. Solve the corresponding quadratic equation: Solve x2+9x+7=0x^2 + 9x + 7 = 0 using the quadratic formula: x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} Here, a=1a = 1, b=9b = 9, and c=7c = 7.

    Calculate the discriminant: Discriminant=b24ac=924(1)(7)=8128=53\text{Discriminant} = b^2 - 4ac = 9^2 - 4(1)(7) = 81 - 28 = 53 Since the discriminant is positive, there are two real roots: x=9±532x = \frac{-9 \pm \sqrt{53}}{2}

  4. Find the roots: x1=9+532,x2=9532x_1 = \frac{-9 + \sqrt{53}}{2}, \quad x_2 = \frac{-9 - \sqrt{53}}{2} These are the roots of the quadratic equation.

  5. Determine the intervals where the inequality holds: The quadratic x2+9x+7x^2 + 9x + 7 opens upwards (since the coefficient of x2x^2 is positive), so the inequality x2+9x+7>0x^2 + 9x + 7 > 0 holds for xx values outside the interval defined by the roots. Therefore, the solution to the inequality is: x<9532orx>9+532x < \frac{-9 - \sqrt{53}}{2} \quad \text{or} \quad x > \frac{-9 + \sqrt{53}}{2}

Final Answer:

x<9532orx>9+532x < \frac{-9 - \sqrt{53}}{2} \quad \text{or} \quad x > \frac{-9 + \sqrt{53}}{2}

Would you like more details on any of these steps, or do you have any questions?

Related Questions:

  1. How do you solve a quadratic equation by factoring?
  2. What are the properties of the discriminant in the quadratic formula?
  3. Can a quadratic inequality ever have no real solutions?
  4. How does the sign of the leading coefficient in a quadratic equation affect the graph?
  5. What are the methods to solve a quadratic inequality?

Tip:

When solving inequalities, always remember to consider the sign of the quadratic expression and the intervals between the roots.

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Inequalities

Formulas

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

Theorems

Quadratic Formula Theorem

Suitable Grade Level

Grades 9-11