17. What is the value of C so that x^2+15x + c is a perfect square trinomial? A. 30
B. 15/2
C. 15/4
D. 225/4​

D. 225/4

Step-by-step explanation:

To complete the square (a technique that can be applied to many problems!), take half the coefficient of  x  and square the result.

The coefficient of  x  is 15.  Half of 15 is 15/2.  Square 15/2 to get 225/4.

Check:

f(x) has value 150 at x= 0

and 0 at x= 3

so d(f(x))/dt = slope = -150/3 = -50

first, we define the variables:

x: number of years after 1950

f (x): amount of vinyl sold.

then, with the variables defined, we have:

68594 vinyl records were sold in 1958 > f (8) = 68594

91299 vinyl records were sold in 1961 > f (11) = 91299

38720 vinyl records were sold in 1952 > f (2) = 38720

161743 vinyl records were sold in 1967 > f (17) = 161743

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step-by-step explanation: