Question 344675
Hi,

Using the point-slope formula, {{{(y[2] - y[1])/(x[2] - x[1]) = m}}} , 

(7,10) and 9, -2)
{{{(10- (-2))/(7- 9) = m}}}
{{{m=highlight(-6)}}}

(-12,-17) and (-18,-20) 
done in a similar fashion!