Mathematics
OpenStudy (anonymous):

$\sum_{51}^{77} 2i-1$

OpenStudy (anonymous):

whats the process of getting the answer though?

OpenStudy (experimentx):

$2\sum_{55}^{77}i - (77-51)$ ^ this is an Arithmetic sequence with first term 55 and common difference 1

OpenStudy (anonymous):

so all i do now is subtract 77-51?

OpenStudy (experimentx):

$2 \times 55(77-51)(77-51+1)/2 - (77-55)$

OpenStudy (anonymous):

|dw:1338098017386:dw| that was how i was solving it and my answer was 3328 but it was wrong?