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What is the smallest positive integer for x so that f(x)=200(2)* is greater than the value of g(x)=500x+400?

User Quayshawn
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1 Answer

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We have to functions, namely:


f(x)=200(2)^(x) \ and \ g(x)=500x+400

So the problem is asking for the smallest positive integer for
x so that
f(x) is greater than the value of
g(x), that is:


f(x)\ \textgreater \ g(x) \\ \therefore 200(2)^(x)\ \textgreater \ 500x+400

Let's solve this problem by using the trial and error method:


for \ x=1 \\f(1)=400 \\ g(1)=900 \\ Then \ f(1) \ \textless \ g(1) \\ \\ \\ for \ x=2 \\f(2)=800 \\ g(2)=1400\\ Then \ f(2)\ \textless \ g(2) \\ \\ \\ for \ x=3 \\f(3)=1600 \\ g(3)=1900 \\ Then \ f(3)\ \textless \ g(3) \\ \\ \\ for \ x=4 \\f(4)=3200 \\ g(4)=2400 \\ \boxed{Then \ f(4)\ \textgreater \ g(4)}

So starting
x from 1 and increasing it in steps of one we find that:


f(x)>g(x)

when
x=4

That is, the smallest positive integer for
x so that the function
f(x) is greater than
g(x) is 4.
User Marine
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