Type the correct answer in the box.

Solve this equation using the most direct method:

[tex] 3x(x + 6) = -10 [/tex]

Enter your solution in the exact, most simplified form. If there are two solutions, write the answer using the [tex] \pm [/tex] symbol.



Answer :

To solve the equation
[tex]\[ 3x(x+6) = -10, \][/tex]
we follow these steps:

1. Distribute the [tex]\(3x\)[/tex] through the parentheses:
[tex]\[ 3x^2 + 18x = -10. \][/tex]

2. Move all terms to one side of the equation to set it to zero:
[tex]\[ 3x^2 + 18x + 10 = 0. \][/tex]

3. Now, we need to solve the quadratic equation [tex]\(3x^2 + 18x + 10 = 0\)[/tex]. To find the roots of the quadratic equation, we can use the quadratic formula:
[tex]\[ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}. \][/tex]

In our equation, [tex]\(a = 3\)[/tex], [tex]\(b = 18\)[/tex], and [tex]\(c = 10\)[/tex]. Plugging these values into the quadratic formula:

[tex]\[ x = \frac{-18 \pm \sqrt{18^2 - 4 \cdot 3 \cdot 10}}{2 \cdot 3}. \][/tex]

4. First, calculate the discriminant:
[tex]\[ 18^2 - 4 \cdot 3 \cdot 10 = 324 - 120 = 204. \][/tex]

5. Then, take the square root of the discriminant:
[tex]\[ \sqrt{204}. \][/tex]

6. Substitute back into the quadratic formula:
[tex]\[ x = \frac{-18 \pm \sqrt{204}}{6}. \][/tex]

7. Simplify the square root if possible:
[tex]\[ \sqrt{204} = 2\sqrt{51}, \][/tex]
so the formula becomes:
[tex]\[ x = \frac{-18 \pm 2\sqrt{51}}{6}. \][/tex]

8. Simplify the fractions:
[tex]\[ x = \frac{-18}{6} \pm \frac{2\sqrt{51}}{6} = -3 \pm \frac{\sqrt{51}}{3}. \][/tex]

Thus, the solutions to the equation are:
[tex]\[ x = -3 \pm \frac{\sqrt{51}}{3}. \][/tex]