What is the value of k when the expression 3(7 + x) is equivalent 3(x + k)

Lesson 9-3 for items 8-10, a square is drawn in the coordinate plane, with vertices as shown in the diagram. then the square is reflected across the x-axis. -2 4 8. the function that describes the reflection is (x, y) - a. (x, y-3). b. (x, y-6). c. (-x, y). d. (x,- y).