document.write( "Question 72596: Help me solve\r
\n" ); document.write( "\n" ); document.write( "g(h(15))\r
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\n" ); document.write( "g(x)=70
\n" ); document.write( "h(x)= -x^2 + 6x
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Algebra.Com's Answer #51899 by bucky(2189)\"\" \"About 
You can put this solution on YOUR website!
Given:
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\n" ); document.write( "\"g%28x%29=70\" and \"h%28x%29=+-x%5E2+%2B+6x\"
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\n" ); document.write( "You are then asked to find g(h(15))
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\n" ); document.write( "Once you understand the process, you can do this one by inspection. But let's work it
\n" ); document.write( "the \"long\" way. What this problem tells you to do is to first find h(15). To do that means
\n" ); document.write( "to just take the equation for h(x) and substitute 15 for all the x's in the equation.
\n" ); document.write( "Doing that results in:
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\n" ); document.write( "\"h%2815%29+=+-%2815%5E2%29+%2B+6%2A15+=+-225+%2B+90+=+-135\"
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\n" ); document.write( "Now you know that h(15) = -135 and since you are being asked to find g(h(15)) you can
\n" ); document.write( "substitute -135 for h(15). Therefore, you are being asked to find g(-135) which tells you
\n" ); document.write( "to go to the equation for g(x) and substitute -135 every where that x appears in the equation.
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\n" ); document.write( "Note now that there are no x terms in the right side of the equation for g(x). So you can
\n" ); document.write( "write that:
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\n" ); document.write( "\"g%28-135%29+=+70\"
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\n" ); document.write( "because there is nothing on the right side where a substitution can be made. Therefore,
\n" ); document.write( "the answer to your problem is:
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\n" ); document.write( "\"g%28h%28x%29%29+=+g%28-135%29+=+70\"
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\n" ); document.write( "With a little more practice and experience you could have looked at the expression for
\n" ); document.write( "g(x) and recognized that no matter what x was (a number or in this case h(x)) it wouldn't
\n" ); document.write( "change the right side of g(x). g(x) would always be 70.
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\n" ); document.write( "Hope this adds a little to your understanding of terms such as g(x), b(x), m(x), and so forth.
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