Which statements regarding the vertex of a quadratic function are true? select all that apply.
it is the point at which the function has a minimum or a maximum.
it is the point at which the function crosses the r-axis.
it is the point at which the function crosses the y-axis.
it is the point at which the extreme value occurs.
it is the point at which the x-coordinate is zero.
it is the point at which the y-coordinate is zero.

Statement reason 1. δabc is similar to δced. given 2. 3. definition of slope 4. slope of slope of definition of slope 5. slope of × slope of multiplying the slopes 6. slope of × slope of substitution property of equality 7. slope of × slope of simplifying the right side the table contains the proof of the relationship between the slopes of two perpendicular lines. what is the reason for statement 2? a. parallel line segments that meet a common perpendicular line are proportional in length. b. the lengths of vertical and horizontal sides in congruent triangles are in a common ratio. c. trigonometric identities determine the lengths of the legs in a right triangle. d. corresponding side lengths in similar triangles are proportional in length.