Question

Решить неравенство (1/5)^(x-1)+(1/5)^x>=30

Answer 1

(1/5)ˣ⁻¹ (1 + 1/5) ≥ 30
(1/5)ˣ⁻¹ 6/5 ≥ 30
(1/5)ˣ⁻¹  ≥ 30 · 5/6
(1/5)ˣ⁻¹  ≥ 25
5¹⁻ˣ ≥ 5²
1 - x ≥ 2
x ≤ -1