Please show step by step

a)6 ÷2(1+2)
b)48 ÷2(9+3)
c)9-3 ÷⅓ +1

Maria donates a fixed amount, a, to a charity each month. if she donates $300 in 12 months, what is the equation for a? a. a + 300 = 12 b. a × 300 = 12 c. a × 12 = 300 d. a + 12 = 300 e. a + 32 = 100

Pls will give brainliest and all p.s u can zoom in if u cant see plss

Aperpendicular bisector, cd is drawn through point con ab if the coordinates of point a are (-3, 2) and the coordinates of point b are (7,6), the x-intercept of cd is point lies on cd.