Given points C (4,3) and D (2,-5), find the slope of every line parallel to Line CD.

(2,-5) (4,3)

Use the gradient formula.

y2-y1 / x2-x1

3 - (-5) / 4 - 2

8 / 2

Slope = 4

When lines are parallel, they all have the same slope, therefore the slope of every line parallel to CD =4

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Given points R (-2,3) and S (5,1), find the slope of every line perpendicular to Line RS.

Again, gradient formula gives

-2/3

For any line perpendicular. The gradient changes.

In general, all you do is "flip" the gradient (-2/3) upside down so it becomes (-3/2). Then you multiply the new gradient by -1.

Every line perpendicular to RS will therefore be3/2

For example if you don't get me.

A line has slope of -1/2.

Perpendicular lines to that line will be 2.