解方程：80 * 200 + x(1000 - 10x) + 40[800 - 200 - (1000 - 10x)] = 50 * 800 + 9000

To solve this equation, we can start by simplifying both sides:

80 * 200 + x(1000 - 10x) + 40[800 - 200 - (1000 - 10x)] = 50 * 800 + 9000

16,000 + x(1000 - 10x) + 40[600 + 10x] = 40,000 + 9,000

16,000 + x(1000 - 10x) + 24,000 + 400x = 49,000

Combine like terms:

40,000 + 400x + 1000x - 10x^2 + 16,000 + 24,000 = 49,000

Collect like terms and simplify:

-10x^2 + 1400x + 80,000 = 49,000

Rearrange the equation to set it equal to zero:

-10x^2 + 1400x + 31,000 = 0

Now we can solve this quadratic equation. We can factor out -10:

-10(x^2 - 140x - 3100) = 0

Next, we can factor the quadratic equation inside the parentheses:

(x - 170)(x + 18) = 0

Now we can set each factor equal to zero and solve for x:

x - 170 = 0 or x + 18 = 0

x = 170 or x = -18

So the solutions to the equation are x = 170 and x = -18.