tolongg bantuu yaaa,,,

11. sn=n/2×(2a+(n-1)b)
sn = 15/2×(2.7+(15-1)6)
sn = 15/2×(14+(14×6)
sn = 15/2× (14+84)
sn = 15/2×98
sn = 15×49
sn = 735 kursi(c)
12. K = 2(p+l)
102 = 2(2l+l)
102 = 4l+2l = 6l
102/6 =l
17=l
p = 2.l = 2.17=34
L = pxl = 17.34 = 578 (b)
semoga membantu :)