Question 64279
You have a type-o for m's value.
find the constant of variation k.
m varies directly with n; m - 144 when n = 8.
m=kn <---m varies directly with n is written this way.
-144=k(8) <---substitute your values in for m and n and solve for k.
-144/8=8k/8
-18=k
{{{highlight(k=-18)}}}
If you meant m=144 instead of m=-144, just remove all the negatives.  k=18.
Happy Calculating!!!