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

1).90

2).-10

Step-by-step explanation:

1).

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

  3      +     12    +    27    +    48

=90

2). (-5(3)+20)+(-5(4)+20)+(-5(5)+20)+(-5(6)+20)

     (-15+20)  +  (-20+20)  + (-25+20)  +  (-30+20)

           5       +       0         +       -5       +      -10

=-10

.25

step-by-step explanation:

d is the correct answer

step-by-step explanation:

x= 8 because 3x = 3 * 8, and 3*8 = 24