document.write( "Question 389425: Find the x-intercepts of the parabola with vertex (4,-1)and y- intercept (0,15). \n" ); document.write( "

Algebra.Com's Answer #275947 by ewatrrr(24785) $\"\"$ $\"About$

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document.write( "Hi,  
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document.write( "the vertex form of a parabola,  where(h,k) is the vertex
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document.write( "vertex (4,-1)
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document.write( "y =a(x-4)^2 -1
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document.write( "using y-intercept pt(0,15) to find a
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document.write( "15 = a(-4)^2 - 1
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document.write( "16 = a*16
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document.write( " 1 = a
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document.write( "y = (x-4)^2 - 1  OR y = x^2 - 8x + 15
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document.write( "x^2 - 8x + 15 = 0
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document.write( "factoring
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document.write( "(x-3)(x-5) = 0
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document.write( "(x-3) = 0   x = 3
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document.write( "(x-5) = 0   x = 5
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document.write( "x-intercepts are Pt(3,0) and pt(5,0)
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