1. what is the sum of the series?
2. what is the sum of the series?

So for finite series like these, you just plug in each number for k that it tells you. The first says the sum of 3k^2 from k=1 to k=4. Just plug integer k between 1 and 4 into the equation and add them together:

3(1^2)+3(2^2)+3(3^2)+3(4^2)=90

Same for the next one, except this is for all values of k between 3 and 6:
(-5(3)+20)+(-5(4)+20)+(-5(5)+20)+(-5(6)+20)=-10

X=3 and y=4 is the answer