Math Problem Statement

4x2 + 10x − 3 = 0 by completing the square

Solution

To solve the quadratic equation 4x2+10x3=04x^2 + 10x - 3 = 0 by completing the square, follow these steps:


Step 1: Divide through by the coefficient of x2x^2

The coefficient of x2x^2 is 4, so divide the entire equation by 4 to simplify: x2+104x34=0x^2 + \frac{10}{4}x - \frac{3}{4} = 0 Simplify further: x2+52x34=0x^2 + \frac{5}{2}x - \frac{3}{4} = 0


Step 2: Rearrange the equation

Move the constant term to the other side: x2+52x=34x^2 + \frac{5}{2}x = \frac{3}{4}


Step 3: Complete the square

To complete the square, take half the coefficient of xx, square it, and add it to both sides. The coefficient of xx is 52\frac{5}{2}, so: (522)2=(54)2=2516\left( \frac{\frac{5}{2}}{2} \right)^2 = \left( \frac{5}{4} \right)^2 = \frac{25}{16} Add 2516\frac{25}{16} to both sides: x2+52x+2516=34+2516x^2 + \frac{5}{2}x + \frac{25}{16} = \frac{3}{4} + \frac{25}{16}


Step 4: Simplify both sides

The left-hand side becomes a perfect square trinomial: (x+54)2\left( x + \frac{5}{4} \right)^2 On the right-hand side, find a common denominator to combine the fractions: 34=1216,34+2516=1216+2516=3716\frac{3}{4} = \frac{12}{16}, \quad \frac{3}{4} + \frac{25}{16} = \frac{12}{16} + \frac{25}{16} = \frac{37}{16} Thus: (x+54)2=3716\left( x + \frac{5}{4} \right)^2 = \frac{37}{16}


Step 5: Solve for xx

Take the square root of both sides: x+54=±3716x + \frac{5}{4} = \pm \sqrt{\frac{37}{16}} Simplify: x+54=±374x + \frac{5}{4} = \pm \frac{\sqrt{37}}{4}

Subtract 54\frac{5}{4} from both sides: x=54±374x = -\frac{5}{4} \pm \frac{\sqrt{37}}{4}


Step 6: Combine terms

Combine into a single fraction: x=5±374x = \frac{-5 \pm \sqrt{37}}{4}


Final Answer:

x=5+374orx=5374x = \frac{-5 + \sqrt{37}}{4} \quad \text{or} \quad x = \frac{-5 - \sqrt{37}}{4}


Would you like a breakdown of any specific step?
Here are some related questions you might want to explore:

  1. How is completing the square related to the quadratic formula?
  2. What are the applications of completing the square in real-world problems?
  3. Why is 5±374\frac{-5 \pm \sqrt{37}}{4} in simplest form?
  4. Can this method be used if the quadratic equation is already in vertex form?
  5. How would the graph of this quadratic equation look?

Tip: Always ensure the coefficient of x2x^2 is 1 before completing the square—it simplifies the process significantly!

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations
Completing the Square

Formulas

Quadratic equation standard form: ax^2 + bx + c = 0
Completing the square: (x + p)^2 = q
Square root property: x = ±√q

Theorems

Completing the square method
Square root principle

Suitable Grade Level

Grades 8-10