What is the slope of a line that is perpendicular to the x-axis?

Ineed the answers for these promblems i have

An object's buoyant force and weight mean the same thing.a. trueb. false

If a negatively charged particle is placed at rest in an electric potential field that increases in the positive x-direction, what will the particle do? a. accelerate in the positive x-direction b. remain at rest c. accelerate in the negative x-direction