Lines are always present in Mathematics a so it is important to know how to find the slope of a line. Finding the slope is one of the main topics discussed in Algebra. It could be boring especially when you do not understand the discussions.
Take the following tips to make things clearer to you about how to find the slope of a line and so that you will know if the lines are perpendicular or intersecting to each other.
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Never forget the slope formula: slope = the change in y divided by the change in x. Slope is equal to the rise divided by run or (y2 – y1)/(x2 – x1).
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For example, make use of the slope formula to find the slope of a line that is consists of two points: (4,6) and (9,21). The change in y is 21 – 6 = 15. the change in x is 9 – 4 = 5. So the rise divided by run is 15/5 = 3. That is how simple it is!
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In cases if the two points are not given, you can still solve the equation. There are two ways: the long way and the easy way. Let us take for an example the equation: 3x – y + 15 = 0.
For the long way, find first the two point of the line. Replace x with 0:
3 (0) – y + 15 = 0. Solve for x. 0 – y + 15 = 0; -y = -15; y = 15. now you have one point (0,15). Then solve for y. Let y be equal to 0. 3x – (0) + 15 = 0; 3x = 15; x = 5. the second point is (5,0).
You can now use the slope formula. The change in y is y = 15 – 0, y = 15. the change in x is x = 0 – 5; x = -5, the rise divided by run is 15/-5 = -3. Your slope is -3.
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the first one is a little complicated. Here is the easier way to solve the equation 3x – y + 15 = 0. Change the format of the equation with y = mx + b. So the equation now will look like this, -y = -3x – 15. You can easily identify the slope. The m represents the slope. In the new equation, the m is -3 which is the slope.
Bear in mind that in choosing the dominant point’s coordinates, do not switch them around because it will provide you a wrong answer. See? There are many ways to find the slope. That is how easy to find the slope of a line.