Question 908950
given:

({{{a}}},{{{-a-7}}}) and ({{{a+h}}},{{{-(a-9h)-7}}})

find: the slope {{{m}}}

use {{{(y[2]-y[1])/(x[2]-x[1])}}}


let's 
({{{x[1]}}},{{{y[1]}}})= ({{{a}}},{{{ -a-7 }}}) and

({{{x[2]}}},{{{y[2]}}})= ({{{a+h}}},{{{ -(a-9h)-7 }}})


 {{{(y[2]-y[1])/(x[2]-x[1])= (-(a-9h)-7-(-a-7))/(a+h-a)}}}


{{{(y[2]-y[1])/(x[2]-x[1])= (-cross(a)+9h-cross(7)+cross(a)+cross(7))/(cross(a)+h-cross(a))}}}

{{{(y[2]-y[1])/(x[2]-x[1])= 9h/h}}}

{{{(y[2]-y[1])/(x[2]-x[1])= 9}}}

so, the slope is: {{{m=9}}}