7.15z + 2.3z = ?z i hate math

Ineed in figuring out this problem.

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

The frequency table shows the results of a survey asking people how many hours they spend online per week. on a piece of paper, draw a histogram to represent the data. then determine which answer choice matches the histogram you drew. in order here is the.. hours online: 0-3, 4-7, 8-11, 12-15, and 16-19. frequency: 5, 8, 10, 8, 7 answer for the question is in the picture! : )