Question 1011206
Find a vector perpendicular to the given vector <5,-7,-8> 
there are an infinite number of vectors that are perpendicular to <5,-7,-8>, namely all c1, c2, c3 that satisfy the dot product = 0
5c1 -7c2 -8c3 = 0
for example,
suppose c2=1 and c3=1 then c1 = 3, therefore
<3,1,1> is perpendicular to <5,-7,-8>