1. **State the problem:** Solve the equation $4x = \sqrt{8x + 3}$ for $x$.
2. **Formula and rules:** To solve equations involving square roots, isolate the square root term and then square both sides to eliminate the root. Remember to check for extraneous solutions after squaring.
3. **Isolate and square:**
$$4x = \sqrt{8x + 3}$$
Square both sides:
$$ (4x)^2 = (\sqrt{8x + 3})^2 $$
$$ 16x^2 = 8x + 3 $$
4. **Rearrange into standard quadratic form:**
$$16x^2 - 8x - 3 = 0$$
5. **Use the quadratic formula:**
For $ax^2 + bx + c = 0$,
$$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$
Here, $a=16$, $b=-8$, $c=-3$.
Calculate the discriminant:
$$b^2 - 4ac = (-8)^2 - 4(16)(-3) = 64 + 192 = 256$$
6. **Find the roots:**
$$x = \frac{-(-8) \pm \sqrt{256}}{2 \times 16} = \frac{8 \pm 16}{32}$$
Two solutions:
- $$x = \frac{8 + 16}{32} = \frac{24}{32} = \frac{3}{4}$$
- $$x = \frac{8 - 16}{32} = \frac{-8}{32} = -\frac{1}{4}$$
7. **Check for extraneous solutions:**
Substitute $x=\frac{3}{4}$ into original:
$$4 \times \frac{3}{4} = 3$$
$$\sqrt{8 \times \frac{3}{4} + 3} = \sqrt{6 + 3} = \sqrt{9} = 3$$
Valid.
Substitute $x=-\frac{1}{4}$:
$$4 \times -\frac{1}{4} = -1$$
$$\sqrt{8 \times -\frac{1}{4} + 3} = \sqrt{-2 + 3} = \sqrt{1} = 1$$
Left side is $-1$, right side is $1$, not equal.
So $x = -\frac{1}{4}$ is extraneous.
**Final answer:**
$$x = \frac{3}{4}$$
Solve Radical Equation 24F00F
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.