Help straight lines q

Help I don’t know which one os the answer between the 2nd and 4th option
The gradient is +3/2 but they both have that

(edited 1 year ago)

The 4th option is correct. It's the only option that has a gradient of 3/2 and I think there was a slight miscalculation for the 2nd option since its gradient is -3/2

Reply 2

old_engineer

Original post by Alevelhelp.1

The gradient is +3/2 but they both have that

I would suggest that you double-check that, perhaps rearranging into y = mx + c form.

(edited 1 year ago)

Reply 3

gdunne42

Possibly the easiest way to see if lines are parallel or perpendicular to each other is to rearrange the equations into the form y=mx + c and then compare the values of m (gradient). In this case gradient of L is -2/3

If they are parallel m will be the same

If they are perpendicular then one will have gradient m and the other will be -1/m or if you prefer (gradient of line 1) x (gradient line 2) = -1

Reply 4

DFranklin

If you have a line of the form Ax+By = C then a line perpendicular to it will have the form Bx - Ay = D (or equivalently -Bx + Ay = D).

"Swap the x,y coefficients, negate one of them, the constant is arbitrary".