Which statement about f(x) = x2 + 4x – 21 is true? A. The zeros are – 7and -3, because f (x) = (x + 7)(x + 3)
B. The zeros are 3 and 7, because f(x) = (x – 3)(x – 7)
C.
The zeros are –3 and 7 , because f(x) = (x+3)(x – 7)
D.
The zeros are –7and 3 , because f(x) = (x – 3)(x + 7)

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.