Math Problem Statement

(√(5x+4)-3)/2x≥1

Solution

We are given the inequality:

5x+432x1\frac{\sqrt{5x + 4} - 3}{2x} \geq 1

Step 1: Isolate the square root

Multiply both sides by 2x2x (assuming x0x \neq 0):

5x+432x\sqrt{5x + 4} - 3 \geq 2x

Step 2: Move terms around

Add 3 to both sides:

5x+42x+3\sqrt{5x + 4} \geq 2x + 3

Step 3: Square both sides

Square both sides to eliminate the square root:

5x+4(2x+3)25x + 4 \geq (2x + 3)^2

Now expand the right side:

5x+44x2+12x+95x + 4 \geq 4x^2 + 12x + 9

Step 4: Rearrange the inequality

Move all terms to one side to set the inequality to 0:

04x2+12x+95x40 \geq 4x^2 + 12x + 9 - 5x - 4

Simplify:

04x2+7x+50 \geq 4x^2 + 7x + 5

or

4x2+7x+504x^2 + 7x + 5 \leq 0

Step 5: Solve the quadratic inequality

To solve 4x2+7x+504x^2 + 7x + 5 \leq 0, we first find the roots of the corresponding quadratic equation 4x2+7x+5=04x^2 + 7x + 5 = 0 using the quadratic formula:

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

where a=4a = 4, b=7b = 7, and c=5c = 5. Plugging in these values:

x=7±724(4)(5)2(4)x = \frac{-7 \pm \sqrt{7^2 - 4(4)(5)}}{2(4)} x=7±49808x = \frac{-7 \pm \sqrt{49 - 80}}{8} x=7±318x = \frac{-7 \pm \sqrt{-31}}{8}

Since the discriminant (31\sqrt{-31}) is negative, there are no real solutions for this quadratic equation. This means that 4x2+7x+54x^2 + 7x + 5 is always positive, and it does not satisfy 0\leq 0.

Step 6: Consider the domain

The expression 5x+4\sqrt{5x + 4} requires that 5x+405x + 4 \geq 0, so:

x45x \geq -\frac{4}{5}

Final Answer:

The inequality has no real solution since the quadratic inequality 4x2+7x+504x^2 + 7x + 5 \leq 0 has no real solutions, and the expression 5x+4\sqrt{5x + 4} is defined for x45x \geq -\frac{4}{5}.

Would you like more details or have any questions?

Here are 5 related questions:

  1. How do you solve inequalities involving square roots?
  2. What happens if a quadratic equation has no real roots?
  3. Can inequalities have no solutions? How do you determine that?
  4. How do you interpret the domain when dealing with square roots?
  5. What are the implications of a negative discriminant in a quadratic equation?

Tip: Always check the domain of expressions with square roots before solving!

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Math Problem Analysis

Mathematical Concepts

Inequalities
Square Roots
Quadratic Equations

Formulas

Quadratic formula: x = (-b ± √(b² - 4ac)) / 2a
Square root isolation: sqrt(A) ≥ B

Theorems

Discriminant and Nature of Roots
Properties of Quadratic Inequalities

Suitable Grade Level

Grades 10-12