已知两直线l1:mx+8y+n=0和l2:2x+my-1=0.求满足下列条件的m,n,的值 .(1)l1与l2相交于点(m,-1) (2)l1平行l2

问题描述:

已知两直线l1:mx+8y+n=0和l2:2x+my-1=0.求满足下列条件的m,n,的值 .(1)l1与l2相交于点(m,-1) (2)l1平行l2

(1)l1与l2相交于点(m,-1)
m^2-8+n=0
2m-m-1=0
m=1
n=7
(2)
m/2=8/m≠n/(-1)
m^2=16 m=4或m=-4
m=4 n≠-2
m=-4 n≠2