I never was good at math, so i wanted to ask someone for help, I'm doing 8th grade math, and this is the problem:

-11 + 9b² = 25

If you can help me I will be very grateful!

7. the area of the playing surface at the olympic stadium in beijing isof a hectare. what area will it occupy on a plan drawn to a scaleof 1: 500?

3.4a=57.8 what is the the value of a

Apassenger train and a freight train leave san jose at 3pm, traveling in the same direction. the passenger train is going three times as fast as the freight train. at 6pm they are 240 miles apart. how fast is each travelling? explain your answer and show your