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Consider the quadratic function y=2x2 – 12x + 20.Rewrite the equation in vertex format.

User Ellis
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1 Answer

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24 votes

The function:


y=2x^2-12x+20

has the form:


y=ax^2+bx+c

with a = 2, b = -12, and c = 20.

The vertex form of a quadratic function is:


y=a(x-h)^2+k

where (h,k) is the vertex.

The x-coordinate of the vertex, h, is computed as follows:


\begin{gathered} h=(-b)/(2a) \\ h=(-(-12))/(2\cdot2) \\ h=(12)/(4) \\ h=3 \end{gathered}

The y-coordinate of the vertex, k, is found replacing h into the formula of the function, as follows:


\begin{gathered} k=2h^2-12h+20 \\ k=2\cdot3^2-12\cdot3+20 \\ k=18-36+20 \\ k=2 \end{gathered}

Finally, the quadratic function in vertex form is:


y=2(x-3)^2+2

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