7 + 11 + 15 + ... sampai suku ke-29

7 + 11 + 15
a=7,b=4
U1-U29
=>7,11,15,19,23,27,31,35,39,43,47,51,55,59,63,67,71,75,79,83,87,91,95,99,103,107,111,115,119

Jika ditanya Sn
S29=29/2(7+119)
=29/2(126)=1827

Semoga membantu ya

semoga membantuu yaa.
thankyou