document.write( "Question 315287: For what value of b will the line y=-2x+b be tangent to the parabola y=3x^2+4x-1
\n" ); document.write( "a method requiring the quadratic formula and substitution is required
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Algebra.Com's Answer #225592 by Fombitz(32388)\"\" \"About 
You can put this solution on YOUR website!
Well that's certainly not the easy way.
\n" ); document.write( "You have two equations.
\n" ); document.write( "\"y=3x%5E2%2B4x-1\"
\n" ); document.write( "\"y=-2x%2Bb\"
\n" ); document.write( "Look for the intersection point.
\n" ); document.write( "Set them equal to each other.
\n" ); document.write( "\"3x%5E2%2B4x-1=-2x%2Bb\"
\n" ); document.write( "\"3x%5E2%2B6x-%281%2Bb%29=0\"
\n" ); document.write( "Since the line is a tangent point, the curves only intersect at one point.
\n" ); document.write( "Then x must be a double root and the equation must be a perfect square.
\n" ); document.write( "Complete the square to solve for both x and b.
\n" ); document.write( "\"3%28x%5E2%2B2x%29-%281%2Bb%29=0\"
\n" ); document.write( "\"3%28x%5E2%2B2x%2B1%29-%281%2Bb%29=3\"
\n" ); document.write( "\"3%28x%2B1%29%5E2=1%2Bb%2B3\"
\n" ); document.write( "\"3%28x%2B1%29%5E2=b%2B4=0\"
\n" ); document.write( "The x coordinate for intersection is \"x=-1\"
\n" ); document.write( "and also \"b=-4\"
\n" ); document.write( "\"highlight%28y=-2x-4%29\"
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