y =[ 100- 10(X- 10)](X-8)

=(200- 10x)(x-8)

Finally, a quadratic function is obtained (the square of x is written as x2, and so on).

y=- 10x2+280x- 1600

Find the maximum value of the function and get y=- 10(x- 14)2+360.

Therefore, when the price is 14 yuan, the maximum profit is obtained, and the maximum profit is 360 yuan.