Math Problem Statement

Solve the quadratic equation by completing the square.

2 x squared plus 3 x minus 52x2+3x−5equals=0

Solution

To solve the quadratic equation 2x2+3x5=02x^2 + 3x - 5 = 0 by completing the square, follow these steps:

Step 1: Move the constant term to the other side

First, we rewrite the equation as: 2x2+3x=52x^2 + 3x = 5

Step 2: Divide the equation by the coefficient of x2x^2

To complete the square, we need the coefficient of x2x^2 to be 1, so divide the entire equation by 2: x2+32x=52x^2 + \frac{3}{2}x = \frac{5}{2}

Step 3: Complete the square

Now, take half of the coefficient of xx, which is 32\frac{3}{2}, and square it. (34)2=916\left(\frac{3}{4}\right)^2 = \frac{9}{16} Add 916\frac{9}{16} to both sides of the equation: x2+32x+916=52+916x^2 + \frac{3}{2}x + \frac{9}{16} = \frac{5}{2} + \frac{9}{16}

Step 4: Simplify the right-hand side

To simplify the right-hand side, express 52\frac{5}{2} as 4016\frac{40}{16}, then add: 4016+916=4916\frac{40}{16} + \frac{9}{16} = \frac{49}{16} So, the equation becomes: (x+34)2=4916\left(x + \frac{3}{4}\right)^2 = \frac{49}{16}

Step 5: Solve for xx

Take the square root of both sides: x+34=±74x + \frac{3}{4} = \pm \frac{7}{4}

Step 6: Solve for xx

Now, solve for xx by subtracting 34\frac{3}{4} from both sides: x=34±74x = -\frac{3}{4} \pm \frac{7}{4} This gives two solutions: x=3+74=1orx=374=52x = \frac{-3 + 7}{4} = 1 \quad \text{or} \quad x = \frac{-3 - 7}{4} = -\frac{5}{2}

Final Solution:

The solutions are: x=1orx=52x = 1 \quad \text{or} \quad x = -\frac{5}{2}

Do you want more details or have any questions about this method?

Here are 5 questions that expand on this topic:

  1. What is the difference between completing the square and factoring?
  2. Can completing the square be used for any quadratic equation?
  3. How can the method of completing the square be used to derive the quadratic formula?
  4. What is the geometric interpretation of completing the square?
  5. How does completing the square help in solving equations with complex numbers?

Tip: Completing the square is particularly useful for converting a quadratic equation into vertex form, which can be helpful for graphing parabolas.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations
Completing the Square

Formulas

ax^2 + bx + c = 0
Square root of both sides

Theorems

Quadratic Formula

Suitable Grade Level

Grades 8-10