Is perpendicular to ? explain.

yes, because the slope of is and the slope of is .
yes, because the slope of is and the slope of is .
no, because the slope of is and the slope of is .
no, because the slope of is and the slope of is .

Two lines are perpendicular if and only if the product of their slopes is - 1.

So, you just need to find the slope of each line and find out the product of their slopes.

I will do one example for you.

L1: y = 3x + 5

L2: y = - 3x + 14

L3: y = -x/3 + 14

The slope of a line is the coefficient of the x.

So the slopes are:

L1: slope 3
L2: slope -3
L3: slope -1/3

So now multiply the slopes of each pair of lines:

L1 and L2: 3 * (-3) = - 9 => No, they are not perpendicular

L2 and L3: (-3) * (-1/3) = 1 => No, they are not perpendicular

L1 and L3: (3) *  (-1/3) = -1 => Yes, they are penpendicular.