document.write( "Question 807278: so the question says \"suppose you are told that a parabola goes through the points (-7,11) and (3,11). What is th x-coordinate of the vertex? how do you know?\" \n" ); document.write( "
Algebra.Com's Answer #486521 by lwsshak3(11628)\"\" \"About 
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a parabola goes through the points (-7,11) and (3,11). What is th x-coordinate of the vertex?
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\n" ); document.write( "Vertex form of equation for a parabola: \"y=A%28x-h%29%5E2%2Bk\", (h,k)=(x,y) coordinates of the vertex.
\n" ); document.write( "Assuming A=1
\n" ); document.write( "y=(x-h)^2+k
\n" ); document.write( "plug in given points,(-7,11) and (3,11), on given parabola for 2 equations:
\n" ); document.write( "..
\n" ); document.write( "11=(-7-h)^2+k
\n" ); document.write( "11=(3-h)^2+k
\n" ); document.write( "subtract
\n" ); document.write( "0=49+14h+h^2-9+6h-h^2
\n" ); document.write( "20h+40=0
\n" ); document.write( "20h=-40
\n" ); document.write( "h=-2
\n" ); document.write( "..
\n" ); document.write( "k=11-(3-h)^2
\n" ); document.write( "k=11-5^2=11-25=-14
\n" ); document.write( "..
\n" ); document.write( "x-coordinate of vertex=-2
\n" ); document.write( "y-coordinate of vertex=-14
\n" ); document.write( "Equation: \"y=%28x%2B2%29%5E2-14\" \n" ); document.write( "
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