Math Problem Statement

Solve the inequality 2𝑥^2 − 3𝑥 + 1 < 0 and represent the solution on a number line.

Solution

To solve the inequality 2x23x+1<02x^2 - 3x + 1 < 0, follow these steps:

Step 1: Find the roots of the corresponding quadratic equation

The quadratic equation is: 2x23x+1=02x^2 - 3x + 1 = 0

To find the roots, use the quadratic formula: x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} where a=2a = 2, b=3b = -3, and c=1c = 1.

Substituting the values, we get: x=(3)±(3)24(2)(1)2(2)x = \frac{-(-3) \pm \sqrt{(-3)^2 - 4(2)(1)}}{2(2)} x=3±984x = \frac{3 \pm \sqrt{9 - 8}}{4} x=3±14x = \frac{3 \pm \sqrt{1}}{4} x=3±14x = \frac{3 \pm 1}{4}

So, the roots are: x=44=1andx=24=12x = \frac{4}{4} = 1 \quad \text{and} \quad x = \frac{2}{4} = \frac{1}{2}

Step 2: Analyze the sign of the quadratic expression

The roots divide the number line into three intervals:

  • x<12x < \frac{1}{2}
  • 12<x<1\frac{1}{2} < x < 1
  • x>1x > 1

Determine the sign of 2x23x+12x^2 - 3x + 1 in each interval by testing a point from each interval:

  1. For x<12x < \frac{1}{2} (e.g., x=0x = 0): 2(0)23(0)+1=1(positive)2(0)^2 - 3(0) + 1 = 1 \quad (\text{positive})

  2. For 12<x<1\frac{1}{2} < x < 1 (e.g., x=34x = \frac{3}{4}): 2(34)23(34)+1=2(916)94+1=9894+1=98188+88=18(negative)2\left(\frac{3}{4}\right)^2 - 3\left(\frac{3}{4}\right) + 1 = 2\left(\frac{9}{16}\right) - \frac{9}{4} + 1 = \frac{9}{8} - \frac{9}{4} + 1 = \frac{9}{8} - \frac{18}{8} + \frac{8}{8} = \frac{-1}{8} \quad (\text{negative})

  3. For x>1x > 1 (e.g., x=2x = 2): 2(2)23(2)+1=86+1=3(positive)2(2)^2 - 3(2) + 1 = 8 - 6 + 1 = 3 \quad (\text{positive})

Step 3: Write the solution set

The quadratic expression 2x23x+12x^2 - 3x + 1 is negative between 12\frac{1}{2} and 11, so the solution to the inequality is: 12<x<1\frac{1}{2} < x < 1

Step 4: Represent the solution on a number line

On the number line, the interval (12,1)\left(\frac{1}{2}, 1\right) is represented as follows:

  • Draw a number line.
  • Mark 12\frac{1}{2} and 11 on the number line.
  • Draw an open circle at both 12\frac{1}{2} and 11 (since the inequality is strict, "<").
  • Shade the region between 12\frac{1}{2} and 11.

Do you want any more details or have any questions?

Here are five relative questions to expand on this topic:

  1. How would the solution change if the inequality were 2x23x+102x^2 - 3x + 1 \leq 0?
  2. What is the graphical representation of the function y=2x23x+1y = 2x^2 - 3x + 1?
  3. How do you solve a quadratic inequality when the discriminant is negative?
  4. What does it mean when the quadratic expression has no real roots?
  5. How can you use the vertex form of a quadratic function to solve inequalities?

Tip: Always check the sign of the quadratic expression in each interval to correctly determine where it is positive or negative.

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Math Problem Analysis

Mathematical Concepts

Quadratic Equations
Inequalities
Number Line Representation

Formulas

Quadratic Formula

Theorems

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Suitable Grade Level

Grades 9-12