How to Find the Equation of a Line

Hello friends today we are going to discuss the topic  How To Find The Equation Of A Line, for finding the equation of a line we need  to  have the knowledge of the three parameters  but before talking about the parameters we will be seeing that what actually is the equation of line,

Y = mx +c

(know more about Linear equation, here)

With the help of this equation we can the equation of line passing through two points with a slope, the direction of x will always be horizontal and the direction of y will always be vertical, in the above equation m is the slop of the given line, if a line passing through the origin then its equation will be

Y = mx

If the value of m is 3 then the equation of line is y – 3x = 0

Now suppose we are having two points as (x1, y1) and (x2, y2) and we are asked to find the equation of the line then we can find the equation of line as

y – y1= m (x – x1)

Here the value of m will be = y2 – y1 /x2 – x1

So we can rewrite our line equation as

y – y1 = (y2 – y1 /x2 – x1) * (x –x1)

if we have two points as (1,2) and (2,3) and we are asked two find the equation of line passing through these points then  the equation will be

y – 2 = m (x – 1)

Now we have to find the value of m, so the value of m will be

m = y2 – y1 /x2 – x1

m = 3-2 /2-1

m = 1

Now we will put the value of m in above equation,

y -2 = x -1

y –x =1

This is the required equation of line.

If you are going through, ICSE sample paper then please focus on word problem solver it is very important from exams point of view

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