document.write( "Question 1113240: find the x intercepts of the parabola with vertex (-1,-16) and y intercept (0,-15). use equation (y-k)=a(x-h)^2 \n" ); document.write( "

Algebra.Com's Answer #728256 by Boreal(15235) $\"\"$ $\"About$

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y=a(x-h)^2+k is the standard form, so h=-1 and k=-16
\n" ); document.write( "y=a(x+1)^2-16
\n" ); document.write( "putting (-1, -16) into vertex makes y+16=a(x+1)^2
\n" ); document.write( "x intercepts are where y=0. Where y=-15, x=0, so 1=a(1)^2. Therefore, a=1\r
\n" ); document.write( "\n" ); document.write( "a(x+1)^2=16
\n" ); document.write( "x+1=+/-4, since a=1
\n" ); document.write( "x=3, -5
\n" ); document.write( "(3, 0) and (-5, 0) ANSWER
\n" ); document.write( "The parabola is x^2+2x-15
\n" ); document.write( "That gives a vertex of (-1, -16) and the y-intercept of -15
\n" ); document.write( " $\"graph%28300%2C300%2C-10%2C10%2C-20%2C20%2Cx%5E2%2B2x-15%29\"$
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