document.write( "Question 450318: find the x-intercepts of the parabola with vertex (-5,80) and y intercept (0,-45)
\n" ); document.write( "round to the nearest hundreth\r
\n" ); document.write( "\n" ); document.write( "i have no idea how to do this problem please help! \n" ); document.write( "
Algebra.Com's Answer #309850 by lwsshak3(11628)\"\" \"About 
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find the x-intercepts of the parabola with vertex (-5,80) and y intercept (0,-45)
\n" ); document.write( "round to the nearest hundreth
\n" ); document.write( "..
\n" ); document.write( "Standard form for a parabola: y=A(x-h)^2+k, with (h,k) being the (x,y) coordinates of the vertex.
\n" ); document.write( "For given problem, (h,k)=(-5,80).
\n" ); document.write( "We can then use point (0,-45) for x and y to solve for A
\n" ); document.write( "-45=A(0+5)^2+80
\n" ); document.write( "-45=A(25)+80
\n" ); document.write( "25A=-45-80=-125
\n" ); document.write( "A=-5
\n" ); document.write( "Equation of given parabola:
\n" ); document.write( "y=-5(x+5)^2+80
\n" ); document.write( "solving for x-intercepts (also known as roots or zeros)
\n" ); document.write( "Set y=0, then solve for x
\n" ); document.write( "0=-5(x+5)^2+80
\n" ); document.write( "-5(x+5)^2=-80
\n" ); document.write( "(x+5)^2=-80/-5=16
\n" ); document.write( "Taking sqrt of both sides
\n" ); document.write( "x+5=±√16=±4
\n" ); document.write( "x=-5-4=-9
\n" ); document.write( "or x=-5+4=-1
\n" ); document.write( "ans:
\n" ); document.write( "x-intercepts of given parabola: -9 or -1
\n" ); document.write( "See graph below to visually relate to the algebra above: (Note the y-intercept, and the two x-intercepts seen in the graph\r
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\n" ); document.write( "\n" ); document.write( "\"+graph%28+300%2C+300%2C+-12%2C+10%2C+-100%2C+100%2C+-5%28x%2B5%29%5E2%2B80%29+\" \n" ); document.write( "
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