First, multiply both sides by -50 to get it.
-50y = x2-8 100 x+ 1050000
Then match the box program on the left to get it.
-50y = x2-8 100 x+ 16402500- 16402500+ 1050000
Get it after completion
-50y =(x-4050)2- 16402500+ 1050000
After further sorting, we get.
50y= 15352500-(x-4050)2
Because the square of (x-4050) is nonnegative, this function has a maximum only when X=4050.
Therefore, when X=4050, the monthly income of the leasing company is the largest.
At this time Y= 15352500/50=307050.
So the highest monthly income is 307,050 yuan.
All the above are calculated by hand.