Express the product as a sum or difference.cos 3x cos 6x
A. 
(cos 9x - cos 3x)
B. cos2 12x2
C. 
(cos 9x - sin 3x)
D. 
(cos 3x + cos 9x)
Answer: D
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Find the center, radius, and intercepts of the circle.x2 + y2 - 2x + 4y - 7 = 0
A. (h, k) = (1, -2), r = 2
x-int: x = 1 ± 2
; y-int: y = -2 ± 
B. (h, k) = (-1, 2), r = 12
x-int: x = 1 + 2
; y-int: y = -2 + 
C. (h, k) = (-1, -2), r = 2
x-int: x = 1 + 2
; y-int: y = -2 + 
D. (h, k) = (1, -2), r = 2
x-int: x = -1 ± 2
; y-int: y =2 ± 
Use a calculator with a 
key to solve the problem.The function f(x) = 90e-0.2x + 10 models the percentage of information, f(x), that a particular person remembers x weeks after learning the information. a) Substitute 0 for x and, without using a calculator, find the percentage of information remembered at the moment it is first learned. b) Find the percentage of information that is remembered after 4 weeks. Round to the nearest thousandth of a percent.
A. a) 10%; b) 10.449% B. a) 50%; b) 210.299% C. a) 90%; b) 40.440% D. a) 100%; b) 50.440%
Identify the number as prime or composite.181
A. Prime B. Composite
Write an equation for the hyperbola.x-intercepts (±5, 0); center at origin; passing through (5
, 6)
A. 
- 
= 1
B. 
- 
= 1
C. 
- 
= 1
D. 
- 
= 1