Question

• Which of the following equations represents a line that is perpendicular to

Answer 1

Answer:

C

Step-by-step explanation:

The equation of a line in slope- intercept form is

y = mx + c ( m is the slope and c the y- intercept )

y = - 4x + 9 ← is in slope- intercept form

with slope m = - 4

Given a line with slope m then the slope of a line perpendicular to it is

$m_{perpendicular}$ = - $\frac{1}{m}$ = - $\frac{1}{-4}$ = $\frac{1}{4}$, hence

y = $\frac{1}{4}$ x + c ← is the partial equation of the perpendicular line

To find c substitute (4, 5) into the partial equation

5 = 1 + c ⇒ c = 5 - 1 = 4

y = $\frac{1}{4}$ x + 4 ← equation of perpendicular line → C