<PRE><B>Question 218207</B>
 Can someone help me with this please. IF f(x)=3x+1, and g(x)=(x^*2+5x)^*-1/2, find g(f(x)). Any explanation on how to do it would be appreciated..
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By x^*2 I suppose you mean x squared.  Use x^2 instead.
g(x)=(x^2+5x)^-1/2
Substitute f(x), which is 3x+1, for x
{{{g(f(x)) = ((3x+1)^2 + 5(3x+1))^(-1/2)}}}
= {{{(9x^2 + 6x + 1 + 15x + 5)^(-1/2)}}}
= {{{(9x^2 + 21x +6)^(-1/2)}}}
or, {{{1/sqrt(9x^2+21x+6)}}}
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