The cellular phone service for a business executive is $80 per month plus $.40 per minute of phone use over 900 min. for a month in which the executive's cellular phone bill was $100.40, how many minutes did the executive use the phone?

Which statements are true? check all that apply. the line x = 0 is perpendicular to the line y = –3. all lines that are parallel to the y-axis are vertical lines. all lines that are perpendicular to the x-axis have a slope of 0. the equation of the line parallel to the x-axis that passes through the point (2, –6) is x = 2. the equation of the line perpendicular to the y-axis that passes through the point (–5, 1) is y = 1.