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# Completing the square maths GCSE - negative or positive point?

Hi, I'm very confused on an aspect about completing the square.

When you are finding the minimum of the graph/equation, are the y and x values negative or positive, and vice versa for finding the maximum.

Any help would be appreciated thank you.

### 2 Answers

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- PuzzlingLv 71 month agoFavourite answer
The sign of the coefficient on the x² term tells you the type of parabola:

- if 'a' is positive (like y = 3x²), then you have an upward-facing parabola and the vertex is a *minimum* with the rest of the graph above it.

- if 'a' is negative (like y = -3x²), then you have a downward-facing parabola and the vertex is a *maximum* with the rest of the graph before it.

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