Find answers to your questions and expand your knowledge with IDNLearn.com. Ask any question and receive timely, accurate responses from our dedicated community of experts.

how can you tell if two equations for parallel lines or perpendicular lines. please explain?

Example:
x+y+7
x-y=3
are those parallel or perpendicular or none


Sagot :

To find out if they are parallel we need to see if the gradient is the same, to do this we need to get y in terms of x:
assuming the first equation is x+y+7=0
y=-x-7
and
y=x-3
The gradient is the coefficient of x (the number infront of x)
For equation 1 the gradient is -1, and for number 2 it is 1, therefore they are not parallel.
However to check if they are perpendicular we need to see if their gradients multiply to equal -1.
-1*1=-1 therefore they are perpendicular
x + y = 7
x -  y = 3
   2x = 10
    2      2
     x = 5
5 + y = 7
-5       -5
     y = 2
(x, y) = (5, 2)