23. solution: (1) from P=- (x-60)2+4 1, it can be known that you only need to invest 600,000 yuan from 1 10,000 yuan every year, you can get the maximum profit of 4 1 10,000 yuan, and the maximum profit if you don't develop it for five years is p6544. When x=50 in the first two years, the maximum annual profit is: p =-(50-60) 2+41= 400,000 yuan, the profit in the first two years is: 40× 2 = 800,000 yuan, and the net profit after road construction is: 800-50× 2 =-200,000 yuan. And if the remaining (100-x) ten thousand yuan is put into overseas sales, its total profit will be w = [-(x-60) 2+41+(-x2+x+160] × 3 =-3 (x-30). ∴ The maximum profit in five years is 3 195-20 = 3 175 (ten thousand yuan) ... (65,438+02 points) (3) The total profit in five years after planning is 3,654,38+0,750 yuan, and only 2.05 million yuan if the planning scheme is not implemented. ..