bantu ya, sertakan cara

a.
r = [tex] \frac{2}{1} [/tex] = 2


b.
[tex] U_{10} [/tex] = 2(2)^9 = 512


c.
[tex] S_{10} [/tex] = [tex] \frac{2( 2^{10 }-1) }{2-1} [/tex] = 2046