✔ 最佳答案
L1:4x-ky+3=0
ky = 4x+3
y = 4x/k +3/k
slope of L1 = 4/k
L2:(3x/k)+(y/3)=1
y/3 = -3x/k + 1
y = -9x/k + 3
slope of L2 = -9/k
As L1 and L2 is mutually perpendicular, the product of the slopes equals -1, i.e. -1 = (4/k)(-9/k)
1 = 36 / k²
k² = 36
k = 6 or -6
As slope of L1 is positive, k=6