2/5^(5x-1) >orequal 25/4

2 answers

Start with = then we will worry about the inequality.

2/5 raised to the 5x-1 = 25/4

take the log of both sides and then use the law of logs.

(5x-1)(log 2/5) = log (25/4)
(5x-1) = log(25/4) divided by (log 2/5)

simplify that then solve for x by adding 1 to both sides and then dividing by5.

Greater than will give your answer to the right on the number line
2/5^(5x-1) >= 25/4
8 >= 5^2*5^(5x-1)
8 >= 5^(5x+1)
5x+1 <= log8/log5
x <= (log8/log5 - 1)/5