We want to find the axis of symmetry of the function;

STEP 1:
The equation for the axis of symmetry of a line is given as;

From the equation, a = 6 and b = -3, so,
STEP 2: Insert the values of a and b into the equation to obtain;

CONCLUSION:
Therefore, we see that the axis of symmetry is the line;
Answer:
A. change in a dependent variable
4 = (r-2) t
8 = (r+2) t
4 = (r-2) * [8/(r+2)]
4 = (8r-16)/ (r+2) . . .multiply by 2
4r + 8 = 8r - 16
4r = 24
r = 6
hope this helps