x+$\frac{4}{(9.13)}$ +$\frac{4}{(13.17)}$+$\frac{4}{(17.21)}$+...+$\frac{4}{(41.45}$ = 10
=>x+ ($\frac{4}{(9.13)}$ +$\frac{4}{(13.17)}$+$\frac{4}{(17.21)}$+...+$\frac{4}{(41.45}$ )= 10
=>x+( $\frac{1}{9}$ -$\frac{1}{13}$ +$\frac{1}{13}$ -$\frac{1}{17}$+..+$\frac{1}{41}$+$\frac{1}{45}$ )= 10
=>x+ ($\frac{1}{9}$-$\frac{1}{45}$ )= 10
=>x+ $\frac{4}{45}$= 10
=>x=9 $\frac{41}{45}$
