ANSWER

EXPLANATION
The sum of an arithmetic sequence whose first term and last terms are known is calculated using

From the given information, the first term of the series is

and the last term of the series is

The sum of the first 26 terms is



KFC
Keep Flip Change
Keep the first fraction
3/4
Flip the second fraction(reciprocal)
6/1 -> 1/6
Change the sign
÷ -> ×
So
3/4 × 1/6
Th answer is 3/5. Divide by the GCF (10) to get 3/5
Just combine like terms: all of the x^2 together, all of the x's together and all of the numbers:
3x2+5x2+5x-2-1
8x2+5x-3 simplified, so letter A