Answer: x+8y = -3
Step-by-step explanation:
If we're given an equation in the form Ax+By = C, then the equation Ax+By = D is parallel to the given line. Note the repeat of Ax+By. The only difference is that the right hand side is something else.
For x+8y = -8, anything parallel to this is x+8y = D
Plug in the given point (x,y) = (5,-1) to compute D
x+8y = D
5+8(-1) = D
5-8 = D
-3 = D
D = -3
Therefore the equation x+8y = -3 is parallel to the given line.