What number is the opposite of - 5/12

What is the best way to answer questions with a x expression in the question. for example 3x + 10x=?

Write the equations in logarithmic form 9^4=6,561

Which of the following exponential functions goes through the points (1, 6) and (2, 12)? f(x) = 3(2)x f(x) = 2(3)x f(x) = 3(2)−x f(x) = 2(3)−x