document.write( "Question 388076: Let function(x)be definedas f(x) =xx+bx+c, where bandc are real numbers
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document.write( "determine all pairs(b,c)such that /f(x)/ is less than equal to 8for all x in the interval. /1,9/ \n" );
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Algebra.Com's Answer #275144 by Jk22(389) You can put this solution on YOUR website! f(x) = xx+bx+c is a parabola open upside \n" ); document.write( " \n" ); document.write( "values at the border : y1=b+c+1, y2=81+9b+c \n" ); document.write( "minimum at -b/2 value : ym=-b^2/4+c \n" ); document.write( " \n" ); document.write( "|f(x)| is <=8 if all three value are \n" ); document.write( " \n" ); document.write( "hence the conditions are : |b+c+1|<=8 |81+9b+c|<=8 \n" ); document.write( " \n" ); document.write( "if 1<-b/2<9 which is the same as : -2>b>-18, there should |-b^2/4+c|<8\r \n" ); document.write( "\n" ); document.write( "hence the solution if : \r \n" ); document.write( "\n" ); document.write( "{ (b,c) | |b+c+1|<=8 and |81+9b+c|<=8 and (|b^2/4-c|<=8 if b in [-18,-2]) } \n" ); document.write( " \n" ); document.write( " |