Task 1 the sum Sn of a finite arithmetic series of n terms is Sn=n/2(a1+an) where a1 is the first term and an is the nth term

a. the sum Sn of a finite arithmetic series of n terms is Sn=n/2(a1+an) where a1 is the first term and an is the nth term
b. explain why Sn=na1+n(n-1)/2 d makes sense by explaining how you can extract each of na1 and n(n-1)/2 d from the sum a1+(a1+d)+(a1+2d)+...+(a1+(n-1)d)

Dee used 2 1/3 cups of sugar for a cake recipe. if the amount of sugar the container holds is 3 times the amount she used, does the container hold more than, less than, or equal to 3 cups of sugar? explain.

Solve this riddle: i am an odd number. i an less than 100. the some of my digit is 12. i am a multiple of 15. what number am i?

Sara has been reading about different types of financial grants, including federal pell grants, academic competitiveness grants, smart grants, and teach grants. which statement about these grants is true? filling out a fafsa will not her apply for these grants. she will not have to pay back any funds she receives from these grants. these grants only go to students with less than a 3.0 gpa. she will have to pay back all the funds she receives from these grants.