bond-pricing

Hi - I am a bit stumped on the algebra to go from this general sum of the bond pricing formula: P(C,y,N,m) = P = $\sum_{i=1}^{N} (C/m)(1+y/m)^i + 1/(1+y/m)^N$ To: C/y(1-1/(1+y/m)^N) + 1/(1+y/m)^N Why does the sum become a "1 - "? And if someone can help me figure out how to write latex...

Learning objectives: Distinguish between gross and net realized returns, and calculate the realized return for a bond over a holding period including reinvestments. Define and interpret the spread of a bond, and explain how a spread is derived from a bond price and a term structure of rates...