1st term in expansion of (4n-3m)^5

Super ultra mega important if you can answer this correctly i will give you 100 points but if you don't answer it correctly you'll get a big report. so stay aware and have a nice day!

Suppose a pendulum is l meters long. the time,t,in seconds that it tales to swing back and forth once is given by t=2.01

Solve the following pair of equations for x and y: ax/b_ by /a= a +b; ax - by = 2ab