Question 1036648
Slope, m, is vertical change divided by horizontal change for any two points on a line.


Any two points, (x[i],y[i]) and (x[t],y[t]),

{{{m=(y[t]-y[i])/(x[t]-x[i])}}}

What if, you generalize more, dropping the subscripts for t:
{{{m=(y-y[i])/(x-x[i])}}}
{{{m(x-x[i])=y-y[i]}}}
Symmetric Property of Equality gives
{{{highlight(y-y[i]=m(x-x[i]))}}}, and the sub t variables are now unknown variables, while sub i variables are any given known variables.