What is the basic difference between the lines y = x and y = -x?

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Answer 1 · 2018-03-23T21:34:01

See explanation

Tony B Tony B

Consider $y = x$ $y=x$

The count of $x's$ is 1 so although it is not normally shown we actually have $y=+1x$

This number 1 is the slope (gradient) which is the amount of up or down for 1 along reading left to right on the x-axis.

As the vertical position increases (positive direction) the slope is upwards

Consider $y=-x -> y=-1x$

In this case the the vertical position decreases (negative direction) the slop is downwards.