Graphs of the pair of equations are parallel,?

Question

Tell whether the graphs of the pair of equations are parallel, perpendicular or neither.

7 x + 3 y = 6

3 x - 7 y = 9

Select the correct answer:

neither

perpendicular

parallel

Answer 1

7 x + 3 y = 6

3y = 6 - 7x

y = 2 - (7 / 3)x

Gradient - 7 / 3.

3 x - 7 y = 9

7y = 3x - 9

y = 3x / 7 - 9 / 7

Gradient 3 / 7.

As the product of the gradients is - 1, the lines are perpendicular.