Question 1113240
{{{(y-k)=a(x-h)^2}}}
{{{(y-(-16))=a(x-(-1))^2}}}
{{{y+16=a(x+1)^2}}}
{{{y=a(x+1)^2-16}}}
When {{{x=0}}},
{{{-15=a(0+1)^2-16}}}
{{{-15=a-16}}}
{{{a=1}}}
So,
{{{y+16=(x+1)^2}}}
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*[illustration grt1.JPG].

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So,
{{{0+16=(x+1)^2}}}
{{{(x+1)^2=16}}}
{{{x+1=4}}} and {{{x+1=-4}}}
{{{x=3}}} and {{{x=-5}}}
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*[illustration grt2.JPG].

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