Question

Are y=x and y+x=0 perpendicular?​

Answer 1

we have ,

y = x => x - y = 0

we have ,

slope =

- (co-efficient of x ) / (co-efficient of y)

and we know that , if two lines are perpendicular to each other then the product of their slope is -1 .

=> Slope of x - y = 0

is ,

m1 = -(1)/(-1) = 1

and slope of x+y = 0 is ,

m2 = -(1)/(1) = -1

as , m1 × m2 = -1

Hence , we can conclude that lines

=> x+y = 0 and x-y = 0 are perpendicular to each other .