Question 399586
f(x)= −2x^2− 4x + 15
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y intercept, when x=0 is 15
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x intercepts when y=0:
x=(-2-sqrt(34))/2, x=(-2+sqrt(34))/2 See below.
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f(x)=a(x-h)^2+k the standard form. The vertex is the point (h,k)=-2(x^2+2x)+15
=-2(x^2+2x+1-1)+15 completing the square
=-2(x^2+2x+1)+2+15
=-2(x+1)^2+17 the standard form.
a=-2, h=-1, k=17
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(-1, 17) vertex.
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Ed
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 *[invoke quadratic "x", -2, -4, 15]