Question

Is the line 3x + 4y + 7 = 0 perpendicular to the line 28x – 21y + 50 = 0?

Answer 1

3x + 4y + 7 = 0

`=>` 4y = –3x – 7

`=> y = -3/4 xx -7/4`

Slope of this line = `(-3)/4`

28x – 21y + 50 = 0

`=>` 21y = 28x + 50

`=> y = 28/21x + 50/21`

`=> y = 4/3x + 50/21`

Slope of this line = `4/3`

Since, product of slopes of the two lines = –1, the lines are perpendicular to each other.