document.write( "Question 1020946: Hi there\r
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document.write( "My question is: For each pair of functions, obtain a formula for f(g(x)) and also for g(f(x))\r
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document.write( "f(x)=2x+3
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document.write( "g(x)=3x+2\r
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document.write( "Can you show ALL your working to perhaps help me to understand better - would be very much appreciated
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document.write( "Thanks so much \n" );
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Algebra.Com's Answer #636745 by FrankM(1040)![]() ![]() You can put this solution on YOUR website! I am going to borrow a strategy from the Calculus for dummies author - \r \n" ); document.write( "\n" ); document.write( "For f(g(x)) think of \r \n" ); document.write( "\n" ); document.write( "f(x)=2x+3 as f(stuff)=2(stuff)+3 in other words, the f(stuff ) function says to take that stuff, double it and add 3.\r \n" ); document.write( "\n" ); document.write( "but here, stuff=g(x)=3x+2\r \n" ); document.write( "\n" ); document.write( "so f(stuff)=2(stuff)+3 just needs the substitution, stuff=3x+2 and \r \n" ); document.write( "\n" ); document.write( "f(g(x))=2(3x+2)+3 = 6x+7\r \n" ); document.write( "\n" ); document.write( "Now, let's check real quick with one substitution X=1.\r \n" ); document.write( "\n" ); document.write( "f(x)=2x+3 \n" ); document.write( "g(x)=3x+2 \r \n" ); document.write( "\n" ); document.write( "g(1)=3(1)+2=5 \n" ); document.write( "f(5)=2(5)+3=13\r \n" ); document.write( "\n" ); document.write( "f(g(1))=6x+7= 13 (check)\r \n" ); document.write( "\n" ); document.write( "Now the next one needs less explaining.\r \n" ); document.write( "\n" ); document.write( " g(f(x))\r \n" ); document.write( "\n" ); document.write( "g(f(x))=3(2x+3)+2= 6x+11 << don't forget to check. \r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |