What is the logarithmic form of 81=3^4

Dylan and dusty plan to take weekly surfing lessons together. if the 2-hour lessons are $20 per person and they plan to spend $100 each on new surfboards, what is the maximum number of lessons the two can take if the total amount spent for lessons and surfboards is at most $480?

Aplot of land in the shape of a vertical ellipse has a pole at each focus. the foci are 8 feet from the center. if the plot of land is 34 feet across the vertical axis, then it is (a.24 b. 30 c. 32 d. 36) feet across the other axis. the eccentricity of the ellipse traced by the boundary of this plot, rounded to the nearest thousandth, is (a.0.543 b.0.515 c.0.471 d. 0.459)

(10 divided by 2) times 7 plus 5 minus 4? ?