Respuesta :

y = mx + b, where m is the slope

A. x = 18
The slope is undefined.

B. 2y - 6x = 0
2y = 6x
y = 3x
The slope is 3.

C. y = -9
y = 0x - 9
The slope is 0.

D. y = x
y = 1x
The slope is 1.

Equation A has an undefined slope.