document.write( "Question 82952: Find the x-intercepts and the vertex of the parabola.\r
\n" ); document.write( "\n" ); document.write( "f(x) = 4x^2 - 56x + 160 \n" ); document.write( "
Algebra.Com's Answer #59705 by ankor@dixie-net.com(22740)\"\" \"About 
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Find the x-intercepts and the vertex of the parabola.
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\n" ); document.write( "f(x) = 4x^2 - 56x + 160
\n" ); document.write( "y = f(x)
\n" ); document.write( "y = 4x^2 - 56x + 160
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\n" ); document.write( "you can simplify it by dividing equation by 4, you have:
\n" ); document.write( "x^2 - 14x + 40 = 0
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\n" ); document.write( "Factors easily to:
\n" ); document.write( "(x - 10)(x - 4) = 0
\n" ); document.write( "x Intercepts:
\n" ); document.write( "x = +10
\n" ); document.write( "and
\n" ); document.write( "x = +4
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\n" ); document.write( "Find the axis of symmetry: x = -b/(2a), in this equation a=1; b=-14
\n" ); document.write( "x = -(-14)/(2*1)
\n" ); document.write( "x = +14/+2
\n" ); document.write( "x = + 7 is the axis of symmetry
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\n" ); document.write( "Use x = 7 to find the vertex.
\n" ); document.write( "You have to find the vertex using the original equation, (not the simplified eq)
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\n" ); document.write( "Substitute 7 for x in y = 4x^2 - 56x + 160
\n" ); document.write( "y = 4(7^2) - 56(7) + 160
\n" ); document.write( "y = 4(49) - 392 + 160
\n" ); document.write( "y = 196 - 392 + 160
\n" ); document.write( "y = -36
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\n" ); document.write( "The vertex x/y coordinates are +7, -36
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\n" ); document.write( "Did this make sense to you? Any questions? \n" ); document.write( "
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