document.write( "Question 953542: The function f is a fifth-degree polynomial with
\n" ); document.write( "the x-intercepts -4, 1, and 7,
\n" ); document.write( "y-intercept 112 and
\n" ); document.write( "f (x) ≥ 0 for x ≤ 7\r
\n" ); document.write( "\n" ); document.write( "I know it would have to have (x+4)(x-1)(x+7) and possibly either squared or cubics for exponents but I am confused about how I would insert the 112 and the f (x) ≥ 0 for x ≤ 7. I don't understand what those last two are asking me to do to make it true.\r
\n" ); document.write( "\n" ); document.write( "Thanks
\n" ); document.write( "

Algebra.Com's Answer #582349 by MathLover1(20850)\"\" \"About 
You can put this solution on YOUR website!
given:
\n" ); document.write( "a fifth-degree polynomial with
\n" ); document.write( "the x-intercepts \"-4\", \"1\", and \"7\",
\n" ); document.write( "y-intercept \"112\" and
\n" ); document.write( "\"f%28x%29+%3E=+0\" for \"x%3C=+7+\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " By hypothesis, \"f%28x%29\" has factors \"%28x+-%28-4%29%29\", \"%28x+-+1%29\", and\"+%28x-7%29\" by the Factor Theorem.\r
\n" ); document.write( "\n" ); document.write( "==> \"f%28x%29+=+%28x+%2B+4%29%28x+-1%29%28x-7%29+%2Ag%28x%29\" for some 2nd degree polynomial \"g%28x%29\".\r
\n" ); document.write( "\n" ); document.write( "To determine \"g%28x%29\":\r
\n" ); document.write( "\n" ); document.write( "We need \"f%28x%29%3E=+0\" for \"x+%3C=+7\".\r
\n" ); document.write( "\n" ); document.write( "==> \"+%28x+%2B+4%29%28x+-1%29%28x-7%29+%2Ag%28x%29%3E=+0\" for \"x+%3C=+7\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Note that each factor is negative for some \"x+%3C=+7\".
\n" ); document.write( "There a few ways to deal with this; here is one way.\r
\n" ); document.write( "\n" ); document.write( "Note that both \"x+%2B+4\" and \"x+-+1\" change signs when \"x+%3C=+7\", while \"x+-7\" does not.\r
\n" ); document.write( "\n" ); document.write( "Since we need \"g%28x%29\" to be quadratic, we can take \"g%28x%29+=+A%28x+%2B+4%29%28x+-1%29\" for some constant \"A\".\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Now, we have \"f%28x%29+=+A%28x+%2B+4%29%5E2+%28x-+1%29%5E2+%28x+-7%29\" for some \"A\".\r
\n" ); document.write( "\n" ); document.write( "Note: that we have not changed the x-intercepts by repeating some of the factors \r
\n" ); document.write( "\n" ); document.write( "Since \"%28x+%2B+4%29%5E2+%28x+-1%29%5E2\" is never negative, needing \"f+%28x%29+%3E=+0\" for \"x+%3C=7\" reduces to needing \"A%28x+-7%29+%3E=0\" for \"x%3C=7\".\r
\n" ); document.write( "\n" ); document.write( "*This is guaranteed if \"A+%3C+0\".\r
\n" ); document.write( "\n" ); document.write( "Finally, we use \"f%280%29+=+112\" to determine \"A\":
\n" ); document.write( "\"A+%2A+4%5E2+%28-1%29%5E2+%28-7%29+=+112\"
\n" ); document.write( "\"A+%2A+16+%281%29+%28-7%29+=+112\"
\n" ); document.write( "\"A+%2A+%28-112%29+=+112\"
\n" ); document.write( "\"A++=+112%2F-112\"
\n" ); document.write( "==>\"+A+=+-1\", which is indeed negative.\r
\n" ); document.write( "\n" ); document.write( "Hence, we can take \r
\n" ); document.write( "\n" ); document.write( "\"f%28x%29+=+%28-1%29%28x+%2B+4%29%5E2+%28x+-+1%29%5E2+%28x+-+7%29\"\r
\n" ); document.write( "\n" ); document.write( "\"f%28x%29+=-x%5E5%2Bx%5E4%2B41x%5E3%2B31x%5E2-184x%2B112\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\r
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "
\n" );