Question

Tolongin dong yg dicentang aja...plus rumus...makasih

Answer 1

7,11,15,19....43
a=7  b=4  un=43
Un=a+(n-1)b
43=7+(n-1)4

9=n-1....n=10

Sn=1/2 n(a+Sn)=1/2 10(7+43)=250


204,210,216 ............ 300

300=204+(n-1)6
16-n-1...n-17