Question

两条直线L1:(m+3)x+2y=5-3m,L2:4x+(5+m)y=16,当L1与L2垂直时M为何值?

Answer 1

[-(m+3)/2]*[-4/(5+m)]=-1,且(m+3)(5+m)≠0

2(m+3)/(5+m)=-1

2m+6+m+5=0

m=-11/3