12544=n/2 *(2*1+(n-1)*2) n=112 So Last term=a+(n-1)*d=1+(112-1)*2 =223

In the sequence of numbers 4,7,-7,....., the first term is 4. Each even numbered term is 3 more than the previous term.Each odd numbered term after the first is -1 times the previous term. What is the sum of the first 22 terms?

Find the value of x and y if

[40/(x+y)] + [2/(x-y)] = 5 [25/(x+y)] - [3/(x-y)] = 1