The roots of the equation
are
and
while the roots of the equation

For the first equation αβ = 2/8 = 1/4   and α+β = -(-1/8) = 1/8

for the second equation  (α-2)(β -2)  = n/m and  (α-2 + β-2) =  3/m

(α-2)(β -2) = 
αβ + 4 - 2(α+β)  Substituting values for αβ and α+β obtained earlier we have:-
1/4 + 4 - 2(1/8) = 4 1/4 - 1/4  = 4  
so n/m = 4(1)

(α-2 + β-2) = α + β - 4 = 1/8 - 4 = -3 7/8 = 3 / m
so 3 / m  = -3 7/8 (2)

from equation (2):-    m =  -24/31

and therefor n =  4 * -24/31 = -96/31

The algebra is a bit messy  but i think its right

the formula of a slope:

we have the points (-2, 7) and (2, 3). substitute:

answer: the slope is equal -1.