[Mathematics] Linear equation: slope-intercept form

Slope-intercept form
Linear equation are any function that can be expressed in this form (named slope-intercept form)

y=mx+b

where m is the slope and b is y-intercept. if we plot the function on graph you would found it's a straight line:

This is an image from Math is fun website, since this function is a straight line so let use this graph to found out the function in slope-intercept form.
Step 1)
Let pick 2 points from the graph to found out slope the line. I select points (0,1) and (1,3):

Use the formula m

 Use slope formula found out the slope:

put x1=0,  x2=1, y2=3,  y1=1 into the formula:

we get slope of this line is 2.

Step 2) find out the y-intercept, it's 1 in this graph

Step 3) put m=2 (slope =2) and b=1 (y-intercept=1) into the formula y=mx+b, we would get

y=2+1

so the function of this line is y=2x+1.

Reference:

Image from :
https://www.mathsisfun.com/algebra/linear-equations.html
https://www.pinterest.com/pin/651473902321977776/