NapkinCalc

Algebra 1

Lines & slope

continues from lesson 1 — values defined earlier in the course stay live here

A line is a rate: slope m says how much y changes per step of x, and the intercept b says where it starts. Two points pin down the whole line.

x1=1x_{1} = 1
y1=3y_{1} = 3
x2=5x_{2} = 5
y2=11y_{2} = 11
m:=(y2−y1)/(x2−x1)m := (y_{2} - y_{1}) / (x_{2} - x_{1}) = 22 rise over run
b:=y1−m∗x1b := y_{1} - m * x_{1} = 11 slide back to x = 0
m * x + b
051015-202468

the line through both points — move a point and watch it tilt