Find the slope of a line perpendicular to 2y= -8x +8

Re-arrange the equation 4y - 3x = 8 in the form y = mx + cy = 3/4x +2

The gradient is 3/4

Now we need to work out the gradient of the 2nd line. Remember that when 2 lines are perpendicular the product of their gradients is -1. Let's call the gradient of the second line m.

3/4m = -1m = -4/3

In the question we are told that the line passes through the point (0, 2). This means that the line crosses the y axis at +2.

So the equation of the line that is perpendicular to 4y - 3x = 8 is y = - 4/3x + 2

Finding the gradient of a line between two points

To find the gradient of a line we need to know how many it goes up, for every one across.

Example

Find the gradient of the line joining (1,3) to (4,9).

As we go from (1,3) to (4,9) the y value increases by 6, and the x value increases by 3. So the line goes 6 up for 3 across. So this line has a gradient of 6/3 = 2.

Use this technique to answer the following question:

QuestionLine A goes through the points (4, 9) and (1, 3). Find the perpendicular line through the point (2, 0).

Exact Form:  

7 /4

Decimal Form:  

1.75

Mixed Number Form:  

1    3 /4

Sorry No Step-by-step explanation