Math Problem Statement

Solve the quadratic equation using the quadratic formula: x^2 + 4x - 7 = 0.

Solution

The given quadratic equation is:

x2+4x7=0x^2 + 4x - 7 = 0

We will solve it using the quadratic formula, which is:

x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}

For the equation x2+4x7=0x^2 + 4x - 7 = 0, we have the following coefficients:

  • a=1a = 1
  • b=4b = 4
  • c=7c = -7

Step 1: Calculate the discriminant

The discriminant is given by b24acb^2 - 4ac.

Discriminant=424(1)(7)=16+28=44\text{Discriminant} = 4^2 - 4(1)(-7) = 16 + 28 = 44

Step 2: Apply the quadratic formula

Now, substitute the values into the quadratic formula:

x=4±442(1)=4±442x = \frac{-4 \pm \sqrt{44}}{2(1)} = \frac{-4 \pm \sqrt{44}}{2}

Since 44=211\sqrt{44} = 2\sqrt{11}, we simplify further:

x=4±2112x = \frac{-4 \pm 2\sqrt{11}}{2}

x=2±11x = -2 \pm \sqrt{11}

Final Solution:

The two solutions are:

x1=2+11x_1 = -2 + \sqrt{11} x2=211x_2 = -2 - \sqrt{11}

These are the exact solutions to the quadratic equation.

Would you like further details or have any questions? Here are 5 related questions to consider:

  1. How do we determine the nature of the roots from the discriminant?
  2. What is the significance of the quadratic formula in solving equations?
  3. How can you approximate the solutions of the quadratic equation numerically?
  4. Can you factor this quadratic equation instead of using the formula?
  5. What are some practical applications of solving quadratic equations?

Tip: Always check the discriminant before solving; it gives insight into the number and type of solutions (real or complex).

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations
Discriminant

Formulas

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

Theorems

Quadratic formula theorem

Suitable Grade Level

Grades 8-10