To learn a function, you must learn to remember the expressions and images (including shapes and quadrants) of the function. )

Proportional function image: straight line passing through the origin

When k (scale coefficient) > 0, the image passes through the first three quadrants.

When k < 0, the image passes through two or four quadrants.

K (proportional coefficient) is not equal to 0.

Please refer to the following website for details.

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