document.write( "Question 556504: f(x)= -4x^2-8x+3\r
\n" ); document.write( "\n" ); document.write( "is this a minmum or a maximum
\n" ); document.write( "what is the value \n" ); document.write( "
Algebra.Com's Answer #362180 by prateekagrawal(56)\"\" \"About 
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f(x) = -4x^2 -8x +3
\n" ); document.write( "f(x) = -4(x^2 +2x) +3
\n" ); document.write( "f(x)= -4 (x^2 + 2x +1 -1) +3
\n" ); document.write( "f(x)= -4(x+1)^2 -4(-1) +3
\n" ); document.write( "f(x) = -4(x+1)^2 +4 +3
\n" ); document.write( "f(x) = -4(x+1)^2 +7
\n" ); document.write( "here (x+1)^2 is a whole square term... which will always be positive.
\n" ); document.write( "so, -4(x+1)^2 is always negative.
\n" ); document.write( "so, at x= -1 , f(x) =7 this is the maximum value of this...\r
\n" ); document.write( "\n" ); document.write( "second method:
\n" ); document.write( "f(x)= ax^2 +bx +c
\n" ); document.write( "if a>0 then minimum value
\n" ); document.write( "and if a<0 then maximum value.
\n" ); document.write( "and value is = f(-b/2a)
\n" ); document.write( ".
\n" ); document.write( "so, here a=-4 <0 so, maximum value....
\n" ); document.write( ".
\n" ); document.write( "and value is -(-8)/2(-4) = -1.
\n" ); document.write( "so,
\n" ); document.write( "f(-1) = -4(-1)^2 -8(-1)+3
\n" ); document.write( "f(-1) = -4+8+3
\n" ); document.write( "f(-1) = 7. \n" ); document.write( "
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