Which of the following equations describes a line that is perpendicular to y=x+4?
Answers.
A) y = x − 4  B) y = −2 − x  C) y = 4x  D) y = 4x+1  E) y = 1/x + 4
Two perpendicular lines have slopes that are inverse reciprocals of each other.   The slope of y=x+4 is 1 so the slope of a perpendicular line will be -1.   The answer is y = −2 − x.
<result>B</result>
Which of the following equations describes a line that is perpendicular to y=x+4?