How to find the equation of a line given one point and a slope

Guess what, I am not a Math student and when I was a kid and during my teenage years. I love math but it was my biggest nightmare and the most difficult subject I was taught. I am an adult now and every day even though the subject is hard, I keep improving day after day because I want to learn and this was also necessitated by the fact I study Information Technology and so I have to do deal with computer architecture and some maths. So as the title of this post goes by, I am going to teach you how to determine and find the equation of a line given or passing through one point


Example 1: -

Let's find the equation of the line with a gradient or slope as it is generally regarded of 4 passing through a given point (3, -2)


Rule Number 1:

When solving problems in relation to slope, you have to apply the law of BODMAS sign result which is as follows


When multiplying numbers:

positive × positive = positive
negative × negative = positive
positive × negative = negative
negative × positive = negative

Rule Number 2:

When given a point for example(3, -2), always remember that the first value represent x1 and that is 3 while the second represent y1 which is 2 and so we have (x, y).


The general formula for solving this type of problem is given as


y - y1 / x - x1 = m or

y - y1
--------    = m (gradient or slope)
x - x1

And the final equation has to be in form of  a straight line which is y = mx + c


So going by the general formula, you should have

y - (-2)
---------   = 4/1 (there is an invisible one for every integer or whole number)
x - 3

= y + 2 (remember -(-2) implies -1 * -2 = 2 and so there is an invisible value of 1)
   -------- = 4/1
    x - 3

What you are going to do next is applying the law of cross multiplication and so you have the output as

1(y + 2) = 4(x - 3) which is also equal to

1y or y + 2 = 4x - 12

and so applying the rule of transposition and formulae, we have to subtract both side by 2 which will give us y + 2 - 2 = 4x - 12 - 2 and the final output and answer is

y = 4x - 14 because 2 - 2 = 0 and also -12 + -2 = -14