To solve this equation for x, we need to first simplify the equation by expanding the square term on the left side.

1/2 - 3/40 * (x - 2)^2 = 1/5
1/2 - 3/40 * (x^2 - 4x + 4) = 1/5
1/2 - 3/40 * x^2 + 3/10 * x - 3/10 = 1/5

Next, we need to combine like terms and get all terms on one side of the equation.

1/2 - 3/40 * x^2 + 3/10 * x - 3/10 = 1/5
-3/40 * x^2 + 3/10 * x - 3/10 = 1/5 - 1/2
-3/40 * x^2 + 3/10 * x - 3/10 = 1/10

Now, we can multiply through by 40 to get rid of the fractions.

-3x^2 + 12x - 12 = 4

Rearranging the equation to set it equal to zero:

-3x^2 + 12x - 16 = 0

Now, we can solve this quadratic equation using the quadratic formula:

x = (-b ± √(b^2 - 4ac)) / 2a

In this case, a = -3, b = 12, and c = -16. Plugging these values into the formula:

x = (-12 ± √(12^2 - 4(-3)(-16))) / 2(-3)
x = (-12 ± √(144 - 192)) / -6
x = (-12 ± √(-48)) / -6
x = (-12 ± 4√3i) / -6
x = 2 ± 2√3i

Therefore, the solutions to the equation are x = 2 + 2√3i and x = 2 - 2√3i.