Question 233554
y= x2 + 4x - 7
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y intercept (x=0) = -7
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x intercept (y=0):
x^2+4x-7=0
x^2+4x  =7
x^2+4x+4=7+4 completing the square.
(x+2)^2=11
x+2=+-sqrt(11)
x=-2+sqrt(11), x=-2-sqrt(11)
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x^2+4x-7
=(x^2+4x+4)-4-7 completing the square again.
=(x+2)^2-11 standard form of the quadratic.
=a(x-h)^2+k standard form of the quadratic.
The vertex is (h,k)=(-2,-11)

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Ed
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{{{graph(500,500,-10,10,-12,8,x^2+4x-7)}}}