Question

Write the slope & y-intercept form: through: (6, -5), slope = undefined

Answer 1

An undefined slope means a vertical line because:

The slope is the angle between the positive direction of the x axis and the line.

When angle is 90° the slope is:

m = tan ( 90° )

m → ∞

This notation means that m tends towards infinity.

The equation of the vertical line passing through ( 6 , - 5 ) is:

x = 6

y coordinate is not important because for each coordinate y, x = 6