Someone help me with this pls

Which of the following is closest to 32.9 x 7.5? a: 232 b: 259 c: 220 d: 265

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

X=-3y-5 3x+9y=7 how can u solve this?