Are the lines y=-x-2 and 4x+4y=16 perpendicular? Explain

A. Yes; their slopes have product - 1

B. No; their slopes are not opposite reciprocals

C. yes; their slopes are equal

D. No; their slopes are not equal

First rearrange the second equation into the form y = mx + b (where m = slopeof the graph of the equation) : -

4x + 4y = 16

4y = - 4x + 16

y = - x + 4

now compare the slope with

y = x - 2

slope of the first one is - 1 and slope of the second is 1

slopes have product of 18-1 = - 1 so the 2 lines are pependicukar

A is correct