Question

If the lines x/3 + y/4 = 7 and 3x + ky = 11 are perpendicular to each other. find the value of k.

Answer 1

slope of line 1 = -4/3

slope of line 2 = -3/k

Product of slopes must be -1 if the lines are perpendicular

-4/3 x -3/k = -1

k = -4

Answer 2

Answer : -4

Step-by-step explanation:

m1 = x/3 + y/4 = 7 take LCM

x/3 × 12 + y/4 × 12 = 7

4x + 3y = 7

m1 = - 4/3 = 3/4 m1 m2 are perpendicular

m2= -3/k = k/3

m1 × m2 = -1

3/4 × k/3 = -1

3k = -12

k = -12/3

k = -4