document.write( "Question 941039: A banner is in the shape of a right triangle of area 63 in^2. The height of the banner is 4 inches less than twice the width of the banner. Find the height and the width of the banner. \n" ); document.write( "
Algebra.Com's Answer #573654 by macston(5194)\"\" \"About 
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W=width of banner; H=height of banner=2W-4; A=Area of banner=1/2WH=63 sq in
\n" ); document.write( "Substitute for H first equation)in the area equation and solve for W:
\n" ); document.write( "1/2WH=63 sq in
\n" ); document.write( "1/2W(2W-4)=63 sq in
\n" ); document.write( "\"%281%2F2%29%282W%5E2-4W%29=63+in%5E2\"
\n" ); document.write( "\"W%5E2-2W=63+in%5E2\" Subtract 63in^2 from each side
\n" ); document.write( "\"W%5E2-2W-63in%5E2=63in%5E2-63in%5E2\"
\n" ); document.write( "(((W^2-2W-63in^2=0}}}\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "\n" ); document.write( "
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation \"aW%5E2%2BbW%2Bc=0\" (in our case \"1W%5E2%2B-2W%2B-63+=+0\") has the following solutons:
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\n" ); document.write( " \"W%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca\"
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\n" ); document.write( " For these solutions to exist, the discriminant \"b%5E2-4ac\" should not be a negative number.
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\n" ); document.write( " First, we need to compute the discriminant \"b%5E2-4ac\": \"b%5E2-4ac=%28-2%29%5E2-4%2A1%2A-63=256\".
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\n" ); document.write( " Discriminant d=256 is greater than zero. That means that there are two solutions: \"+x%5B12%5D+=+%28--2%2B-sqrt%28+256+%29%29%2F2%5Ca\".
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\n" ); document.write( " \"W%5B1%5D+=+%28-%28-2%29%2Bsqrt%28+256+%29%29%2F2%5C1+=+9\"
\n" ); document.write( " \"W%5B2%5D+=+%28-%28-2%29-sqrt%28+256+%29%29%2F2%5C1+=+-7\"
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\n" ); document.write( " Quadratic expression \"1W%5E2%2B-2W%2B-63\" can be factored:
\n" ); document.write( " \"1W%5E2%2B-2W%2B-63+=+1%28W-9%29%2A%28W--7%29\"
\n" ); document.write( " Again, the answer is: 9, -7.\n" ); document.write( "Here's your graph:
\n" ); document.write( "\"graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+1%2Ax%5E2%2B-2%2Ax%2B-63+%29\"

\n" ); document.write( "\n" ); document.write( "So W=9,-7
\n" ); document.write( "First Let's consider 9
\n" ); document.write( "When W=9, H=2W-4=2(9)-4=14
\n" ); document.write( "ANSWER Width is 9 in and Height is 14 in, a tall narrow right triangle pointing upward and to the right.
\n" ); document.write( "CHECK:
\n" ); document.write( "Area=1/2WH=63 in sq
\n" ); document.write( "Area=1/2(9in)(14in)=63 in sq
\n" ); document.write( "Area=1/2(126in sq)=63 in sq
\n" ); document.write( "Area=63 in sq=63 in sq, Check
\n" ); document.write( "Next, let's consider -7. At first this seems an unlikely width, but if we consider on an X,Y co-ordinate plane right is the positive direction, it means this banner points left. So solving for height:
\n" ); document.write( "H=2W-4=2(-7)-4=-14-4=-18, again negative, so pointing down
\n" ); document.write( "So we have a banner of Width=7 in and Height=18 in pointing left and downward
\n" ); document.write( "CHECK:
\n" ); document.write( "Area=1/2WH=1/2(-7in)(-18 in)=63 in sq
\n" ); document.write( "Area=1/2(126 in sq)=63in sq
\n" ); document.write( "Area= 63 in sq=63 in sq Check
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