document.write( "Question 1204639: use f(x)=-2x+4 and g(x)=x^2-3x to determine or simplify the following
\n" ); document.write( "(a)f(3)
\n" ); document.write( "(b)g(-2)
\n" ); document.write( "(c)g(f(3))
\n" ); document.write( "(d)f(g(x))
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Algebra.Com's Answer #841028 by math_tutor2020(3817)\"\" \"About 
You can put this solution on YOUR website!

\n" ); document.write( "Part (a)\r
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\n" ); document.write( "\n" ); document.write( "f(x) = -2x+4
\n" ); document.write( "f(3) = -2(3)+4
\n" ); document.write( "f(3) = -6+4
\n" ); document.write( "f(3) = -2\r
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\n" ); document.write( "Part (b)\r
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\n" ); document.write( "\n" ); document.write( "g(x) = x^2-3x
\n" ); document.write( "g(-2) = (-2)^2-3(-2)
\n" ); document.write( "g(-2) = 4+6
\n" ); document.write( "g(-2) = 10\r
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\n" ); document.write( "Part (c)\r
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\n" ); document.write( "\n" ); document.write( "g(f(3)) = g(-2) because f(3) = -2
\n" ); document.write( "We replace f(3) with -2\r
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\n" ); document.write( "\n" ); document.write( "Then refer to part (b) to find that g(-2) = 10 which must mean g(f(3)) = 10\r
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\n" ); document.write( "\n" ); document.write( "Here's another approach
\n" ); document.write( "g(x) = x^2-3x
\n" ); document.write( "g(x) = (x)^2-3(x)
\n" ); document.write( "g(f(x)) = ( f(x) )^2-3( f(x) )
\n" ); document.write( "g(f(x)) = (-2x+4)^2-3(-2x+4)
\n" ); document.write( "g(f(x)) = (4x^2-16x+16)+(6x-12)
\n" ); document.write( "g(f(x)) = 4x^2+(-16x+6x)+(16-12)
\n" ); document.write( "g(f(x)) = 4x^2 - 10x + 4\r
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\n" ); document.write( "\n" ); document.write( "Then,
\n" ); document.write( "g(f(x)) = 4x^2 - 10x + 4
\n" ); document.write( "g(f(3)) = 4(3)^2 - 10(3) + 4
\n" ); document.write( "g(f(3)) = 4(9) - 10(3) + 4
\n" ); document.write( "g(f(3)) = 36 - 30 + 4
\n" ); document.write( "g(f(3)) = 6 + 4
\n" ); document.write( "g(f(3)) = 10
\n" ); document.write( "Your steps do not need to be as verbose as shown above.\r
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\n" ); document.write( "Part (d)\r
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\n" ); document.write( "\n" ); document.write( "f(x) = -2x + 4
\n" ); document.write( "f(x) = -2( x ) + 4
\n" ); document.write( "f(g(x)) = -2( g(x) ) + 4
\n" ); document.write( "f(g(x)) = -2( x^2-3x ) + 4
\n" ); document.write( "f(g(x)) = -2x^2 + 6x + 4 \r
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\n" ); document.write( "\n" ); document.write( "Summary of the four answers
  1. f(3) = -2
  2. g(-2) = 10
  3. g(f(3)) = 10
  4. f(g(x)) = -2x^2 + 6x + 4
Each answer can be verified with GeoGebra.
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