Question 677757
<img src="http://latex.codecogs.com/gif.latex?\large \sum _{j=3}^{5} f_{2j} = f_{2*3} + f_{2*4} + f_{2*5}" title="\large \sum _{j=3}^{5} f_{2j} = f_{2*3} + f_{2*4} + f_{2*5}" />


<img src="http://latex.codecogs.com/gif.latex?\large \sum _{j=3}^{5} f_{2j} = f_{6} + f_{8} + f_{10}" title="\large \sum _{j=3}^{5} f_{2j} = f_{2*3} + f_{2*4} + f_{2*5}" />


<img src="http://latex.codecogs.com/gif.latex?\large \sum _{j=3}^{5} f_{2j} = 8 + 21 + 55" title="\large \sum _{j=3}^{5} f_{2j} = f_{2*3} + f_{2*4} + f_{2*5}" />


<img src="http://latex.codecogs.com/gif.latex?\large \sum _{j=3}^{5} f_{2j} = 84" title="\large \sum _{j=3}^{5} f_{2j} = f_{2*3} + f_{2*4} + f_{2*5}" />