What is the sum of the series?

First one

[ first term  +  last term ] * number of terms   / 2

first term  = 3(1)   = 3

last term  = 3(5)   = 15

Sum    =   [ 3 + 15 ]  * (5)   / 2 =    18 * 5 / 2 =     45

Second one....     

first term  =  2(1)^2  - 4 =    -2

second term = 2(2)^2 - 4 = 4

third term = 2(3)^2 - 4 = 14

last term  =  2(4)^2 - 4=      28

Sum  =  44