Calculus
posted by Dan on .
P(x)= x^3+15x^248x+450, x>/3 is an approximation to the total profit (in thousands of dollars) from the sale of x hundred thousand tires. find the number of hundred thousands of tires that must be sold to maximize profit.

0=3x^2+30x48
0=x^210x+16
0=(x8)(x2)
x=8, or x=2
check that.