What is the axis y=x^2-21x-4 ?

The axis y=x^2-21x-4 is x= 21/2

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axis y=x^2-21x-4

axis

y = x^{2} - 21 x - 4

x = \frac{21}{2}

Solution steps

y = x^{2} - 21 x - 4

Rewrite

y = x^{2} - 21 x - 4

in the standard form

4 \cdot \frac{1}{4} (y - (- \frac{457}{4})) = (x - \frac{21}{2})^{2}

Therefore parabola properties are:

(h, k) = (\frac{21}{2}, - \frac{457}{4}), p = \frac{1}{4}

Parabola is of the form

4 p (y - k) = (x - h)^{2}

and is symmetric around the

y

-axis

Axis of symmetry is a line parallel to the

y

-axis which intersects the vertex:

x = \frac{21}{2}

y = - x^{2} + 150 x - 2000

y = - 3 x^{2} - 12 x - 5

y = x^{2} - 5

x^{2}

y = - \frac{1}{4} x^{2} + 8 x - 4