Linear Equations

Equation of a Straight Line

The equation of a straight line is usually written this way:

y = mx + b

What does it stand for?

Slope (or Gradient)                                  Y Intercept

How do you find "m" and "b"?

1. b is easy: just see where the line crosses the Y axis.
2. m (the Slope) needs some calculation:

Knowing this we can work out the equation of a straight line: 

Example 01: 

With that equation you can now:
Choose any value for x and find the matching value for y:

when x is 1:

y = 2×1 + 1 = 3

y=3

Or 

When x is 7:

y = 2×7 + 1 = 15

  y=15

Example 02:

Example 03: Straight Line

In fact, this is a special case, and you use a different equation,

not "y=...", 

but
 instead you use "x=..."

x = 1.5

Every point on the line has x coordinate 1.5, that is why its equation is x = 1.5

 

Now, Let's try some exercises!

References:

https://www.mathsisfun.com/equation_of_line.html 

https://www.mathsisfun.com/algebra/index.html