# Thread: line equations , very urgent!

1. ## line equations , very urgent!

Find ( a ) if the line that has these points : (a,-3) and (3,1) is normal
with the line that has these points : (a,-3) and (-1,-2) .

2. Originally Posted by beq!x
Find ( a ) if the line that has these points : (a,-3) and (3,1) is normal
with the line that has these points : (a,-3) and (-1,-2) .
Get the gradient of each line. Check whether the product of the gradients is equal to -1.

3. Originally Posted by beq!x
Find ( a ) if the line that has these points : (a,-3) and (3,1) is normal
with the line that has these points : (a,-3) and (-1,-2) .
A line is perpendicular to the other .

So the product of their gradients will be equal to -1 , then solve for a.