Tìm x

To solve the equation, we can follow these steps:

1. Start by simplifying the equation:
14 - 5 = 12 - 0.4x - 0.16/x

2. Combine like terms:
9 = 12 - 0.4x - 0.16/x

3. Move all terms to one side of the equation:
0 = 12 - 0.4x - 0.16/x - 9

4. Simplify further:
0 = 3 - 0.4x - 0.16/x

5. Multiply through by x to eliminate the fraction:
0 = 3x - 0.4x^2 - 0.16

6. Rearrange the equation to form a quadratic equation:
0 = -0.4x^2 + 3x - 0.16

7. To solve the quadratic equation, we can use the quadratic formula:
x = (-b ± √(b^2 - 4ac)) / (2a)

In this case, a = -0.4, b = 3, and c = -0.16.

8. Substitute the values into the quadratic formula:
x = (-(3) ± √((3)^2 - 4(-0.4)(-0.16))) / (2(-0.4))

9. Simplify further:
x = (-3 ± √(9 - 0.256)) / (-0.8)

10. Continue simplifying:
x = (-3 ± √8.744) / (-0.8)

11. Calculate the square root:
x = (-3 ± 2.956) / (-0.8)

12. Solve for x:
x1 = (-3 + 2.956) / (-0.8) ≈ -0.055
x2 = (-3 - 2.956) / (-0.8) ≈ 7.445

Therefore, the solutions to the equation are approximately x ≈ -0.055 and x ≈ 7.445.