Amy and stephanie were playing a number game. amy picked a number and told stephanie that if she added 9 to the number and multiplied the sum by 3, it would equal 12. which equation could stephanie use to find the number, x?
a.
3(x) + 9 = 12

b.
3(x + 9) = 12

c.
3 + (x + 9) = 12

d.
9(x + 3) = 12