Which correctly completes this number sentence?

3 × 9 = (3 × 5) +

a)(5 × 9)

b)(3 × 4)

c)18

d)(9 - 5)

Suppose a laboratory has a 30 g sample of polonium-210. the half-life of polonium-210 is about 138 days how many half-lives of polonium-210 occur in 1104 days? how much polonium is in the sample 1104 days later? 9; 0.06 g 8; 0.12 g 8; 2,070 g