[填空题]
Bellatrix Aviation manufactures business jhh -v*p 0u5c x7expatue mxh6*/(7vlnets. The profit th e5kpc. .8cvuze company makes, P , in millions of dollars, changes bac u 8.eckv.5zpsed on the number of jets, x , they manufacture per quarter.
The rate of change of the profit made from manufacturing x jets is modelled by
$\frac{\mathrm{d} P}{\mathrm{~d} x}=-0.4 x+16, \quad x \geq 0 $.
In the previous quarter, the company made a profit of 165 million dollars from manufacturing 20 jets.
1. Find an expression for P in terms of x .Therefore we obtain P= $-{a}x^2 + b x - c$;a= ,b= ,c= .
The company has the capacity to increase the number of jets they manufacture.
2. Describe how the profit changes if the company increases manufacturing to over 40 jets per quarter and up to 75 jets per quarter.
