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# Algebra 4.1 & 4.2

1) Use the functions r(t), q(t), and s(t) given to answer the questions below.
r(t)=sqrt(6t+64) q(t)=8t-1 s(t)=3-19t

What is the y-intercept of y=(r-s)(t)?
(0,__)

2) Use f(x)=sqrt(16-x^2) and g(x)=5x^2+8x-4 to answer the following question
Which of the following is in the domain of (f o g)(x)? Select all that apply.
a) x=-2
b) x=1
c) x=0
d) x=-3
e) x=2

3)If (f o g)(x)=7sqrt(x^2+1)represents the composition of two function f(x) and g(x), which of the following could represent f(x) and g(x)? Select all that apply.
a) f(x)=7sqrt(x); g(x)=x^2+1
b) f(x)=sqrt(x+1); g(x)=7sqrt(x)
c) f(x)=7sqrt(7x+1); g(x)=sqrt(x)
d) f(x)=7sqrt(x+1); g(x)=x^2
e) f(x)=x^2; g(x)=7sqrt(x+1)
f) None of these

4) The half-life of a radioactive element is 6.6 hours. How much of a 360 mg sample is left after 26.4 hours?
________mg

5) Which of the following functions could be used to represent a population which grows 2% each year from an initial population of 900?
a) P=900(2)^t
b) P=900(.02)^t
c) P=900(1.2)^t
d) P=900(1.02)^t
e) P=900(.2)^t