Five less than three times the sum of a number and nine is at least 20.

Answer 1

sum of a number and nine ... x+9
three times that ... 3(x+9)
five less than that ... 3(x+9)-5
now finish it off

Answer 2

3(n+9) - 5 <= 20

Answer 3

3(n+9) - 5 >/=20
3 n + 27 - 5 >/= 20
3 n + 22 >/= 20
3 n >/= -2
n >/= -2/3
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check
if n = -2/3
n +9 =27/3 - 2/3 = 25/3
3(n+9) = 25
25-5 = 20 sure enough

Answer 4

at least ... >=