Question

if 5x+3y+7=0,kx-7y+8=0 are perpendicular then k= how much​

Answer 1

Answer:

k= -21/5

Step-by-step explanation:

5x+3y+7=0------------(1)

kx-7y+8=0------------(2)

We know that the slope m of the line ax+by+c=0

=-a/b

Thus slope of line(1) m1=-5/3

and slope of line(2) m2=-(-k/7)=k/7

Line(1) and (2) are perpendicular

so m1*m2=-1

5/3*k/7=-1

5k/21=-1

k= -21/5